Jim Mohr's SCO Companion


Copyright 1996-1998 by James Mohr. All rights reserved. Used by permission of the author.

Be sure to visit Jim's great Linux Tutorial web site at http://www.linux-tutorial.info/

1 Installing and Registering Free SCO

The installation of the Free SCO product on the CD is essentially the same as for any other SCO product. However, the products that you get and the licensing is slightly different. In this chapter we are going to talk specifically about the installation and registration of Free SCO.

Unlike in the first book, I cannot make the assumption that you have installed SCO before. One of the most appealing aspects of this book is that we are providing you a copy of the Free SCO. Since getting the Free SCO may be you primary motivation for buying this book, it is a logical assumption that you have never installed an SCO system before.

Most of the issues that we are going to address I talked about in the first book. However, in the first book it was assumed that you already had a commercial copy of SCO and therefore had the Installation Guide. Since we are giving you a copy of SCO and not providing the Installation Guide, it is a logical assumption that you don't have an Installation Guide to work from. Plus, I don't want to have you flipping back and forth between the two books. Therefore, we are going to go into a lot more detail about the installation in this chapter than we did in the first book.

An important part of this installation is planning. You need to know what you have and what you are going to do with it. The range that this simple statement can cover is amazing. My years in SCO support have taught me that when someone says they know what kind of computer they have can mean anything from being able to say that it's a "Compaq” to being able to describe the chip on each card. For the average person it lies somewhere toward the first end. It is therefore important to gather as much information about your system as possible before you start the installation.

First, it helps you make the right choices during the installation. Second, if you do call into support or post a message on Compuserver you have all the necessary information in front of you.Unfortunately, SCO will does not provide support for the FreeSCO. The only way you can get support is either from a free source like Compuserve, or you have a support contract with SCO.

Knowing what hardware you have is just part of it. You also need to know what software you are going to install. The first response is "Free SCO” or "SCO OpenServer Desktop System” or something similar. For the most part, this is correct. However, the SCO OpenServer Desktop System is a fairly large product and composed of many different packages. Depending on your goal (or size of your hard disk), you may not want or need to install everything. Plus, when you register you free SCO you get licenses for more than just the SCO OpenServer Desktop System. What you get and what it is composed of we'll talk about first.

The Software

The first thing is the operating system itself. Free SCO is a nothing more than the SCO OpenServer Desktop product. You have the same components as you would with the normal OpenServer desktop. Also, you have to get your license from SCO before you install. Since the product is shipped without a license, you have to connect to the SCO Web site to get your license.

Without over simplifying too much, we can say the SCO OpenServer Desktop System is composed of four major components, or products. These products are:

  • Operating System

  • Graphical Environment (the X Windowing System)

  • Network Connectivity

  • Documentation

There are certain portions of the operating system that you cannot do without. However, most of the others can be left out or installed on a piece by piece basis. The nice thing is that the installation program will not let you not install the things that you must have.

If you have a partition of greater than 300MB, then you can install everything on the CD that you get a license for and have plenty of room to spare. Since I have licenses for a range of other SCO products that I wanted to install on top of the Free SCO, I need more space.

Another thing is the products that are provided. In addition to the OpenServer Desktop product, you get a copy of the SCO OpenServer Development System and the Advanced File and Print Server (which allows you to provide file and print servers to MS-Windows based machines.) There are also two other products on the CD that you can install without licenses: SCO Doctor (a system monitoring tool) and ARCServer/Open (a backup package). There are also many other products on the CD.

I need to step back here for a moment. Saying that these products are provided for you is true, but I need to clarify it a little more. When you license the product through the SCO Web site, you are given a license for these three products. However, there are several more products on the CD, including WABI, the Virtual Disk Manager and SMP. You can even install them. However, without the necessary licenses they won't run.

However, with the correct licenses they run just as they would on any other SCO system. The reason is that you are given a license for the SCO OpenServer Desktop system. As far as it is concerned, it cannot tell that you have the free version. The kernel (and the system, in general) supports all of the products that it normally would. In addition to the remainder of the Free SCO, I installed the Virtual Disk Manager and WABI. These work just as they do on my other SCO systems.


One of the first things to do is to get your license from the SCO Web site. As of this writing, there is link on the SCO Home page, announcing Free SCO UnixWare. The page that this link brings you to also contains the necessary information for licensing your of the Free SCO OpenServer Desktop. There is a link, under the heading “License Now:” which will bring you directly to the page where you can get you license. We'll talk more about this shortly.

Note that the only way to register the product is on the SCO Web site. You cannot call, email or fax them to get them to send you the licensing information. The administration costs are just too high. Therefore, you have to have Internet access. If you do not have it, this would be the perfect time to get a CompuServe account. The SCOFORUM on CompuServe is a fantastic source of support and information for the entire range of SCO products. You will then have access to the Web and can get your license information.

Once on the SCO Web site, clicking on the link "Free SCO OpenServer” brings you to a page which contains a lot of introductory information, including frequently asked questions and the release notes. Unfortunately, as of this writing, there is no single file that you can download. Instead, you need to click through the various links to get the information you need. Fortunately, I will be covering the more important issues here, so there is no great need to wade through the SCO Web site.

When you finally reach the form to license your SCO product, you may be intimidated by the amount of information you have to provide. However, considering that filling out this form will save you hundreds of dollars, it's worth the five minutes to fill it out. Once the form is complete, you get a new page that contains the licensing information for the SCO OpenServer Desktop, the SCO OpenServer Development System and the SCO Advanced File and Print Server.

During the installation process there are a few terms that you will need to know. These are related to the licensing information that you got from the page at the SCO Web site.

Prior to the installation, it is a good idea that you have a plan of action. The OpenServer installation guide provides a checklist that you can fill out prior to starting the installation. Since you do not have a copy of the OpenServer Installation guide, I have provide a modified version of this checklist.

Preparing for the Install

I suggest you make a copy of the checklist in Table 0\1 for each system that you install. You can fill in each entry and include it in a notebook. You will notice that there are some very basic questions concerning keyboard language and time zone. It may seem almost too basic to include this type of information in a checklist. However, I can speak from experience that the more you have written down, the less prone you are to making mistakes. Even if the information is “basic.”

Note also that the minimum space mentioned in the SCO documentation is just enough to get installed. You need to consider future growth of the system, as well.


Assigned Value1



Boot-time loadable drivers



Package names:


Installation media

From CD

From Tape

What is the hardware configuration on the install device?


Keyboard language


License Information

From SCO Web Site

License Number

License Code

License Data


Installation Type



Upgrade only valid for existing SCO systems

System name

Must be unique within your network

Domain name

Must be unique if you ever plan to connect to the Internet

Security Profile







Geographic area

Time zone name

Daylight savings time



Hard Disk Config.


For example: Wide-SCSI, PCI




Host adapter

Bus Number



EIDE/IDE Controller



Base Address

Interrupt Vector (IRQ)

DMA Channel


LBA Enabled

EDIE only

SCSI Host Adapter



Base Address

Interrupt Vector (IRQ)

DMA Channel


Where is the termination?

Which device?

Draw out the SCSI bus and label everything, including termination

Hard Disk Setup



Use whole disk


Interactive fdisk/divvy

Hard Disk Layout

Customized or Interactive only

UNIX Partition size (MB)

DOS Partition size (MB)

Other Partition size (MB)

boot filesystem size (MB)

swap space size (MB)

root filesystem size (MB)

Other filesystems size (MB)

Bad Track







See the text for a description of what each of these means.



Operating System

Graphic Environment


Online Doc

You need to know how much space it will take to install all the software. See the text for maximums and some tips.

Network Information

Network Card




For example: Ethernet, TP, Combo


Base Address

If applicable

ROM address

If applicable


If applicable

Base RAM Address

If applicable

RAM size

If applicable

Local Ring Broadcast

Token-ring only

Slot Number

If applicable

IP Address

Must be unique within your network and within Internet if you ever plan to connect to the Internet


Based on the network class you choose. The system should calculate this value for you.

Broadcast address

IPX/SPX Broadcast

IPX/SPX Framing Type

Video Card


Not all are listed. You may need to simply choose something like VGA or find the chipset that your card uses.



Base Address

Normally not needed

Interrupt Vector (IRQ)

Normally not needed

Max resolution

Max colors

Frequencies supported

Selected mode

resolution and colors



Not all are listed. You may need to simply choose something like "other 15”



Max resolution

Max colors

Frequencies supported

Graphic Logic (sco login)



If included on your system will start-up by giving you the graphic logic. Otherwise, you must run startx, to start up X.






Serial, bus, PS/2

Base Address

Bus mice only

Interrupt Vector (IRQ)

Bus mice only

Serial port

Serial, mice only

Bus Mouse IRQ




Keyboard Mouse

High resolution

low resolution

Email System


send mail


Hard disk:




Only for non-SCSI devices


Only for SCSI devices


Only for SCSI devices


Hard disk controller



Base Address

Interrupt Vector (IRQ)

DMA Channel

Table 0\1 Installation Checklist

Before you start you need to check out your system. The very first thing you need to check is the hardware itself. The first question to ask yourself is whether or not the hardware is supported. I’m sure there are a few of you out there who are groaning thinking this is an attempt to blow you off. I talked with many customers while I was in SCO Support that went ballistic when I brought up the question of the hardware being supported.

“It works under DOS!” Is a common response. However, as I have said many times, all that really means is that the hardware is probably not broken. I say “probably” because I have seen defective hardware work under DOS, but not on UNIX. Under DOS a lot of hardware is accessed through the system BIOS. The BIOS is often built especially for that machine. It understands the hardware in a way that SCO doesn’t. Since the SCO device drivers are accessing the hardware directly, the hardware has to behave in a standard way. Otherwise, the SCO device drivers don’t know what to expect. (For more details on the system BIOS, see Chapter 10, The Computer, in the first book)

Does this mean that your no-name hardware won’t work? Not at all. My server is running a fair bit of “unsupported” hardware. Much of it is clones of supported hardware (which causes a lot of grief). However, it works. When I tried to install something that wasn’t supported and it didn’t work, there was no frustration because working was something that wasn’t guaranteed (okay, so there was a little frustration).

There is also the issue of conflicts. SCO is good about being able to install a wide number of cards at their default. The common place for conflicts is with cards of the same type, such as host adapters. However, having the list in front of you will confirm this before you try to install and have something go wrong.

As you can see in the checklist, each card that you have in your system has the same basic set of information that you should record. The key pieces of information are:

  • base address

  • IRQ

  • DMA channel

  • Memory address (if the card has one)

Once you have installed the operating system and it works diligently for six months, the first problems may begin to crop up. Now, what was the model of the hard disk? Rather than digging through a box of papers looking for the invoice, you have it right in front of you.

During the course of the installation, you will have the choice of several different installation types, from fully automatic to fully configurable. For the more advanced system administrators, the fully configurable allows you to control many different aspects of the install. Fully automatic, basically does everything for you; that is, it evaluates your system and essentially makes all the decisions itself. My recommendation is that if you are a novice administrator and there is nothing on the hard disk that you want to save, then the fully automatic is your best choice.

Preparing for the Worst

One thing that many administrator’s don’t plan for is the possibility that things will go wrong. Although, good planning and preparation can prevent many disasters, the most devastating are obviously the ones that you are not prepared for. When doing an upgrade, there will come a point in which backing out is no longer possible. If the new operating system doesn’t boot and you cannot go back to the old one, then you have problems.

One problem that I have had personal experience with is third party device drivers. Although the installation notes for the driver might say that it is for SCO UNIX 3.2. version 4.0 and later, this may not be true. If it is an older card, then what they mean by “and later” is SCO UNIX 3.2 version 4.2 (ODT). In the case of the network card I had it wasn’t true. What I had was an NE2000 compatible that worked fine in ODT. However, it gave me errors when I tried to relink it under OpenServer.

The problems that my brother encountered were much more dramatic. He has a third party filesystem compression software on his system that he uses for his /u filesystem. Although this is a very stable product and he is completely satisfied with it, the version he has was incompatible with OpenServer. As a result, when he tried to relink, it failed. He then tried to load the backup software he had, only to discover that the install script did not work correctly with the OpenServer custom. The choice was either to wait until he got the OpenServer version of the backup software or reinstall ODT. Since his work depends on timely access to his data, his only choice was to re-install. Since he had a complete backup of his system, he was running again within a couple of hours.

This story illustrates two important issues when doing an upgrade. First, be prepared for the possibility that your third party drivers will not work. It is possible that the device was unsupported in ODT, but is now supported in OpenServer. Installing the manufacturer’s driver may not only be unnecessary, it may cause problems. Check the SCO Hardware Compatibility Guide (available on the SCO Web site) or with the hardware vendor.

Keep in mind that the compression software is not a “device” in the traditional sense, despite having drivers. Therefore, you will not find it in the SCO Hardware Compatibility Guide. The best thing to do in cases like this is to talk to the vendor directly.

The other issue is that you must have a complete backup of your system before you start. In my brother’s case, he did have a complete backup. The problem was that the backup software didn’t work in OpenServer. However, since he was prepared before he started the upgrade and had a complete backup, he was running again within a short time. No matter what goes wrong, these backups can get you running again.

One suggestion is to either have the new version of the backup software on hand and make sure that it is compatible with OpenServer or use some SCO tool like tar or cpio. Both the tar and cpio in OpenServer can read the backups created in ODT.

If you have access to CompuServe, you might want to consider downloading the demo copy of Lone-Tar from Library 8. This works with both ODT and OpenServer. This is a demo with a limited lifespan, but not limited functionality. I think you might be pleased enough with it to use it as your standard backup tool.

Doing the Install

Provided in the back of this book you have a CD and a boot disk. For those of you familiar with Open Desktop, you will find that one of the most startling differences between OpenDesktop 3.0 and OpenServer is that OpenServer only boots with a single floppy. I have been doing installs for years. There is supposed to be an N1 and N2 floppy, right? The kernel is almost the size of an entire floppy, so how can you get the kernel and the necessary programs to do an install on less than two floppies? You compress them!

Not only is the kernel compressed, but so are the installation programs. Although a certain amount of time needs to be spent decompressing things, the kernel is uncompressed as it is being loaded. Since you do not have to switch floppies and begin loading that as well, the time you gain more than compensates for the time needed to decompress things. A RAM disk is created and the root filesystem image is loaded into the RAM disk. Like the kernel, this filesystem image is compressed to get it to fit on the floppy. Note that although the files on the floppies are compressed, it is not a compressed filesystem.

When it finally comes time to do the install, the first step is gathering all the documentation together. This includes not only all of the SCO doc but all the handbooks (pamphlets?) that came with your hardware. The next thing to get is a notebook. Here you record all the details about your system configuration. Since you haven’t installed anything, yet, now is a good time to start writing things down. This is the perfect opportunity to write down manufacturer, model, and settings of all the hardware. This is valuable information if you run into problems, either during the install or later. You should also write down the vendor support number if it’s available. Here, again, having everything in one place will save you time later.

Another thing that you absolutely must do is check the hardware configuration through the systems CMOS, PCI setup or EISA config, depending on what kind of system you have. Note that PCI and EISA allow you to configure the cards through the system and not directly on the card. You don't need to guess as what the card is configured at as the setup will show exactly what it is set to. Also, don't expect the operating system to see the hardware if the configurations programs don't.

Next is the checklist that we talked about earlier. Having a completed installation checklist has a couple of benefits. First, it can be a real time saver during the installation. You don’t have to keep bouncing around between the doc and hardware or scratching your head thinking about what a good value for each entry would be. You’ve made all the decisions before and now you just fill in the blanks. You are therefore less likely to input mistakes or guess at what you should answer. In addition, this “forces” you to plan out the upgrade before you start.

The installation is started by inserted the boot disk and booting your machine. You will then see a prompt on you screen that looks like this:


If you do not have any boot time loadable drivers (see below) you can continue simply by pressing return. This will load and run the kernel the floppy and then start the Installation Query Manager (IQM). The IQM is a graphic interface to the installation process. You will be ask a series of questions about the type of installation you want to do, the software you want to install and then configuration parameters based on the software you chose to install. In the following sections we will cover the various sets of questions you will be asked and some of the more common responses.

When you boot from the floppy during the installation, one of the first things you need to consider are Boot-Time Loadable Drivers (BTLD). These are drivers for hardware that is not supported by SCO on the release you are currently installing. However the vendor provides the appropriate drivers which are then linked into the kernel at boot time. These are not necessarily drivers for hardware that you install after the OS is finished, but rather for hardware that you need during the installation. A good example would be the host adapter that your root hard disk is installed on. However, the mechanism used to install BTLDs is not just restricted to the installation. You can install a BTLD at any time. These are just drivers that are loaded at boot time, not just install time. For more details, see the section on BTLDs.

When the kernel has finished loading and the root filesystem is uncompressed, the Installation Query Manager (IQM) is started. Although the IQM in OpenServer is conceptually the same as that for ODT, the new one is much more extensive in terms of both what areas are asked as well as the depth of information you can provide. Once you finish answering the questions, the IQM does the rest of the work.

One very important thing you need to be aware of is that the OpenServer installation does not prompt you to install the release supplement like it does in ODT. You must, instead, go through the Software Manager to install new software. This is very important as the Release Supplement contains the latest corrections to known problems (in English: bug fixes). One thing to keep in mind is that when you add the release supplement in OpenServer, you select “Apply Patch” and not “Add New Software.”

If somewhere during the installation you run into a snag and have to restart the installation, you need to be careful. For example, you may get halfway through the installation and realize you did not leave any room for a /u filesystem. So, you need to restart. The problem, depending on how far you’ve gotten, is that if you power off and reboot from the installation floppy, the system will recognize that it has already reached a particular point and continue on from there. In order to get the system to restart the install from the beginning, you need to enter “restart” at the Boot: prompt.

Boot-Time Loadable Drivers

As their name implies Boot-Time Loadable Drivers (BTLDs) are drivers that are loaded at boot-time. This provides a very effective means of adding drivers to the system that are not contained within the normal distribution. These can be drivers provided by hardware vendors and on occasion, by SCO. Previous versions of SCO provided a BTLD disk with serverl drivers necessary for the installation. In most cases, BTLDs come from third party vendors and are used to support devices that you need to install from, such as SCSI host adapters. (If you don’t need it to install the OS, why not wait until later to install that driver?) Despite this generality, BTLDs can be loaded any time you boot.

You can install the BTLD during the installation when you first start the system by adding the string link to the boot prompt. Without any arguments, the system will prompt you for the name of the package. After the kernel loads, it will prompt you for the floppy containing the BTLD you specified. Alternatively, you can input link=pkg where pkg is the name of the driver you want to link in. In this case, the system will not prompt you again for the name, but will prompt for the disk. If necessary, the system may also prompt you for parameters, such as IRQ or DMA of the card you are installing.

As an example, let's assume I have a Wonder Works host adapter. The package name is “wwha”. The boot string would look like this:

Boot: link=wwha

After the kernel has loaded (but before it starts to execute) the /link program is run. This prompts me to insert the floppy disk containing the BTLD I specified. Next I may be prompted to input values to configure that hardware, such as base address, DMA channel, and interrupt vector. If I input values that conflict with existing hardware, link will scream at me and give me instructions on what I can do to correct the problem.

If you have multiple BTLDs that you wish to load, you can specify them all at the Boot: prompt. The system will then prompt you for each driver, in turn. For example, if you have the wwha and fyha, the bootstrings would look like this:

Boot: link="wwha fyha"

Note that you need to include all the drivers between the double quotes. You can also specify the link command on its own, in which case you will prompt for the names of the package(s) that should be linked.

One common misconception is that once you have added the driver at boot time, then the driver is part of your system for keeps. Well, it is until the next time you relink your kernel. The problem is that the driver is linked into the kernel that is being loaded, but is not made part of your link kit. The next time you reboot, the driver is gone. To get the driver into the link kit and into all subsequent kernels, you need to run the installpkg utility. Here you are prompted to insert the disk containing the BTLD. At this point, all subsequent relinks will include the new driver.

On the other hand, the installation of both ODT and OpenServer should prompt you to reinsert the BTLD disk to add it to the link kit. If so, it becomes part of the system for good. However, if you are not prompted, you will need to run installpkg. You are prompted to insert the disk and input the name of the driver you want to install. Here, too, the system may prompt you to input certain parameters. Once the package is installed, you will need to relink the kernel. See the link_unix man-page for details.

Installation Media

The installation media is the media from where you are going to install the product. Because we have provided you with a CD-ROM, that is probably the media you are going to choose. By default, the media suggested is a SCSI tape drive. By pressing the spacebar, you will be given the list of possible media sources. Use the up and down arrow until you find the appropriate CD-ROM device.

If you select a SCSI CD-ROM you will need to select the adapter type, the SCSI ID and logical unit number (LUN) of the CD-ROM drive. (For details of what this all means, see Chapter 10, The Computer in the first book.) To move between fields, use the tab key. In each case, when you are in the appropriate field, press the space bar to get a list of options.

If you do not need a BTLD for you SCSI host adapter, the system will automatically detect it. If you have more than one? host adapter on your system, you will need to select the appropriate one. Tabel 1-2 shows you a list of more common host adapters that the system will recognize. Note that some host adapters can emulate other ones. For example, the adapter 174x can be configured to emulate a 154x. In this case you would use the 154x driver and not the 174x.




Adaptec 154x, 164x


Adaptec 174x


Adaptec 152x


Adaptec 2940x (7870 Chip)


Adaptec 274x (7770 Chip)


Future Domain 7000


Future Domain 7000ex


Future Domain 1650, 1670, 1680, 600, 700 (1800 Chip)


Future Domain 845, 850, 860, 885 (950 Chip)


Olivetti ESC-1, ESC-2, and EFP Adapter Driver


Storage Plus SCSI-AT (SUMO)


DPT RAID SCSI Host Adapter Driver




386/486 CBUS SCSI


Mylex Disk Array Controller


NCR 53C710 for MCA

Table 1-2 Common SCSI host adapters.

Keyboard language

In my mind, this item is somewhat of a misnomer. A better choice would be keyboard country since the layout of the keyboard is dependent on the country you are in and not the language you speak. For example, the US English keyboard is different from the British English and the German keyboard is different from the Swiss German.

In many cases where there is a difference between countries, the appropriate keyboard is listed under the adjectival form of the country name. For example, you will find the Swiss German keyboard under Swiss and not Switzerland. Additionally, there may be two types of keyboards. The standard type and PS/2. Normally the PS/2 keyboard is specifically for IBM PS/2 machines. However, I have had some non-PS/2 machines that worked better with the PS/2 keyboard.

Which one you select will determine the file that the system uses to configure your keyboard. Despite what the characters on your keyboard say, the signals the keyboard sends are the same between the keyboards of different countries. This is why you have to tell the system to behave differently based on the language of the keyboard. If you are familiar with DOS, this is what the KEYB.SYS command does. By passing it the appropriate country code, it will "convert” the signals sent by the keyboard into the appropriate letter which is then displayed on the screen.

SCO UNIX is no different in this regard. This difference is that the default translation information is stored in the file /usr/lib/keyboard/keys. In addition to that file, the /usr/lib/keyboard contains all of the translation files. When you select a language, the keys file is linked to the file appropriate for that language. Once the system is booted, you can then examine these files to see if the one selected in correct. You can then either link or copy the appropriate files. Keep in mind that you won't be able to access these files until after the installation.

If necessary, you can make changes to these files to make it fit your keyboard. Normally, this is not necessary. However, I have encountered some keyboards that are slightly different than the standard for that country.

NOTE: I would recommend that you copy the file first before making any changes.

License Information

The next step in the installation is the serialization. In OpenServer you no longer have to input your serial number and activation key. Instead you have a license number and license code. In some cases (with certain upgrades), there is license data provided that must also be input during the installation. This is useful information to have when you need to call support, particularly if you don’t already have a support contract.

The License Number is a unique number that identifies each SCO product. Along with it is the License Code, which is used to activate the product. For some products, this is enough. However, for the products provided with the Free SCO, you also get a fairly long string of characters, which is the Licensing Data.

The screen looks like Figure 0-1. All of this information is case sensitive, so it is essential that you type it in correctly. All three of these are provided to you when you register on the SCO Web site. Note that the numbers listed in the example are invalid. Therefore, you can't use them to install.

Figure 0-1 FreeSCO Installation - License Screen

Installation Type

Depending on what you already have on your system, you have a choice between a Fresh install and an Upgrade. The odds are that you will be required to do an Upgrade. I have installed the FreeSCO several times with existing systems on the disk an each time I was told that my system was "not suitable” for an upgrade.

The fresh install will overwrite any existing root filesystem you have. However, you can choose to keep the current sizes of your partitions and filesystems. However, your root filesystem will still get overwritten. That means that all user and configuration information will be gone.

In order to save time, many system administrators chose the upgrade option. Although this upgrade functionality has improved considerably since previous releases, it can’t catch everything. There are many hardware and software products that become unusable after an upgrade and must be reinstalled. In the end, the administrator spends more time cleaning up from the upgrade than was saved by not doing a fresh install.

The alternative is doing an overwrite. This essentially removes all third party drivers and other products installed on the root filesystem as this is completely overwritten. However, it is somewhat faster than a fresh install. The problem is that there is no overwrite option for OpenServer. You either upgrade or do a fresh install.

Personally, I’m not bothered by this. When I do an installation it is always a fresh install. Experience has taught me that the best way to avoid problems is not to let them happen. By doing a fresh install, I am much more aware of the effects each action has on my system. It may take longer initially. However, I am saved grief in the long run.

When you do a fresh install, you must ask some key questions. First, how should the disk be partitioned? If you have only one operating system, then using the entire disk for SCO is reasonable. If not, you need to consider how much will be used for each. The installation procedure of both ODT and OpenServer asks you how big you want different partitions to be. Despite that fact, there is still the question of, “how big?”

One thing to consider is what other software is going to be installed. Some database applications require an entire partition for its own purposes. Others may require their own filesystem. I’ve talked with customers who, after installing the OS discovered that they did not leave the necessary room for their application. They frantically call support asking for some way to change the partition and filesystems without having to reinstall. The answer is no. Therefore, know what your application expects before you start installing the operating system.

The next thing to consider is what other operating systems you are going to install. Although you can create the partitions for other operating systems during the SCO installation, it is much better to install them first and then SCO. You can get away with installing DOS after SCO;, however, if you are going to install OS/2, Windows NT, or Windows 95, these should be installed first. The reason is that they write the partition table differently than SCO or DOS, making the SCO partition inaccessible.

If you are planning to install DOS, you will still be limited to the 32MB partition size if you are still running MS-DOS 3.3. Don’t use any version of MS-DOS 4.x. This doesn’t work well with SCO partitions. If you have anything after MS-DOS 5.0, then the partition size can be anything greater than 3Mb. Keep in mind that if you plan to use DOS DoubleSpace or some other disk compression software, the compressed partition will not be accessible by SCO utilities such as doscp, nor will you be able to mount the DOS filesystem. Also pay attention to which partition is active. I have talked with many customers who have overwritten one or the other partitions. Both DOS and SCO install to the active partition. If you install one and then install the other without first making the other partition active, you end up overwriting the first operating system.

Since DOS can be installed after SCO, some people do. Even if you do remember to switch the active partition prior to installing DOS, some people forget about this later. They are used to booting systems with both DOS and SCO and seeing the SCO Boot: prompt. When the system boots directly into DOS, they have a heart attack and end up calling SCO Support. The way to correct this problem is to simply use DOS’s fdisk to change the active partition to the UNIX partition.

Also keep in mind that when the SCO installation routines create the partitions, that’s all they are doing: creating them. They are not formatting the partition. You must use native DOS programs to do that. Even the dosformat command will not format a DOS partition. This partitioning is done by the fdisk command, although you don’t actually see it doing its work.

When considering the UNIX partition size, you need to also consider the swap and filesystem sizes as well. The size of your swap space needs to be considered carefully. The absolute minimum size is slightly more than the amount of RAM you have. The reason is that if the system should panic, it will dump all of the memory to your swap device. If you do not have a large enough swap space, then you will not get a valid dump image, and it makes tracking down the cause of the crash more difficult. The extra amount is needed to write crash data if the system panics. By increasing it by a megabyte you don’t lose too much space.

Another very important reason for having enough swap is that the kernel will only use as much RAM as it has swap space for. The reason is because there may be a case where a single process needs to take up all of the available RAM. Therefore all of the other processes must be swapped out. If there is not enough swap space, the system runs into trouble.

I’ve seen references that say swap should be one-and-a-half to two times the amount of RAM. Personally, I think this is too much, without a good reason. The swap space should be considered a safety net, not an integral part of your memory system. If you are swapping, performance will suffer. If you think you will need the extra swap space, then consider buying more RAM. That way, you are less likely to swap in the first place.

However, you need to consider growth. If you expect to be increasing your RAM in the future, you should consider this when setting how much space you are going to use for swap. RAM just slides into your system. Increasing swap may require reinstalling the operating system. So, how much do you assign to swap? Good question. My suggestion is twice as much as RAM. The “good reason” I mentioned above is that it is easier to do it now and waste the space than to reinstall later. Another good reason is when there is more than one user running graphical applications. In this case, setting swap to two times RAM is reasonable. If you have all the space taken up on the primary hard disk, you can add a hard disk and use the swap command to add additional swap space.

You also need to keep in mind that swapping takes up system resources. The time to access the hard disk is hundreds of times slower than the time to access RAM. Therefore, if speed is an important consideration, you should think about having enough RAM so you don’t swap.

At this point you also want to consider additional filesystems. With OpenServer, things are complicated already. The first question is how big you want your boot filesystem to be (/dev/boot). This holds a few files and a couple of copies of the kernel. Therefore, it doesn’t need to be too big. However, you need to consider how much the kernels can grow. If you have a 3Mb kernel, then 5Mb for /dev/boot is not enough. However, making it 50Mb is going overboard to the other extreme. Personally, I think 10–15Mb gives you room for a larger kernel, but also gives you room to grow. However, you need to consider that there will probably be at least three kernels here. (15Mb is the default.)

One engineer at SCO mentioned to me that he uses 25Mb. This is because he does a lot of testing and has several different versions of the kernel. Therefore, if you do a lot of tinkering with your system, you may also need a larger /dev/boot filesystem.

The next question is whether you should make additional filesystems. If your application requires a filesystem to itself (usually a raw division), then you definitely need to create it. What about a /u or /home filesystem for your users? There are advantages to having one as well as advantages to not having one.

If you have one, it is easier to come up with a backup schedule if you don’t want to do a full back-up of the system every night. For example, you could back up the whole system once a week, and the /u filesystem with the data every night. In addition, most of the hard disk activity is on the root filesystem. If your data is there and a head crash occurs, you can lose data. By moving your data to another part of the disk, you decrease the likelihood of data loss.

The disadvantage of a separate filesystem is that system accounts such as root or sys have their home directories in /usr. If you put other users in /u or /home, the home directories are in two different places. This may not be such a problem if the system accounts rarely, if ever, log in. The other problem is that creation of the filesystem does not mean that it gets mounted automatically (at least not in ODT). As a result, customers end up calling to SCO Support saying that half their disk is missing. They had created the filesystem, but didn’t run mkdev fs to have it get mounted. Although it is mentioned in the ODT doc that you need to do this, finding it requires that you either know the problem or read the doc cover to cover. OpenServer corrected the problem by asking if you want to create the appropriate entries to automatically mount the filesystem.

The other problem is that the default is to create user home directories in /usr. Therefore, you need to change the HOME_DIR variable in /etc/default/authsh on ODT and in /etc/default/accounts on OpenServer. Personally, I think it’s a good idea to have data on a separate filesystem and keep the root filesystem as static as possible. This makes backup schedules easier, and there is less chance of corruption as the root filesystem is usually the busiest and therefore has a greater potential for corruption.

System Information

The System Information is, as it's name implies, basic information about your system (see Figure 0-2). The first item is the system name. This is the name you are going to call your system. In other words, the host name. However, this is just the host name, not the fully qualified domain name (FQDN). The FQDN is created by taking the system/host name and adding it to the next item: the domain name. This will normally be of the form domainname.com, domainname.edu, or domainname.org. Both of these entries are fairly easy to change, so if you are not sure what to input, you can leave them at the defaults. For more information on domain names, see the section on the Domain Name System in Chapter 9, Talking to other Machines, in the first book.

Figure 0-2 FreeSCO Installation - Basic System Information

Next is the security profile, which determines how secure your system will be. There are four levels available, the default being traditional. This is what you would normally find on a UNIX system. Less secure is the low security profile. More secure is the improved security. This is comparable to a C2 level of security. At the top is high security, which imposes even more restriction than are required by C2. For details see the security section in chapter 4 "Users and User Accounts” in the first book.

One thing to keep in mind is that you can change the security level. However, you can never increase security. When created, each user is given a security profile, which describes the access they have. Unless you specifically change this, the security profile will be kept even if you change levels. So, if you are at a low security level and increase it, there will be users still at the lower level. My recommendation is that for home use, when you are not allowing users from the outside and not providing any Internet services, then either traditional or low security is a good choice.

The Timezone entry is used to set the time zone. Here you can select the geographical area you are in (such as North America, Europe, Asia) and the name of the time zone (EST, CET). There is also an entry to set whether daylight savings time is used in your area.

Preparing your disk

This section of the installation process allows you to configure your hard disk prior to installing the software. Here you select exactly how much of the hard disk the system should take for UNIX. Additionally, you definejust what software the system should install.

Hard Disk Setup.

In the hard disk setup portion, you need to be especially careful if you have existing partitions. The default is "UNIX Only” (see Figure 0-3). This means that the system will create a single UNIX partition, no matter what else is on the disk. Another option is "Customize”, which allows you to specify how large each partition will be. Although the partition table can hold four entries, you can only create three partitions at this point (UNIX, DOS and OTHER). Here, you also create the size of the filesystems within your UNIX partition.

Figure 0-3 FreeSCO Installation - Harddisk Preparation

The last alternative is Interactive fdisk/divvy. The fdisk command is used to partition the hard disk (just like the DOS FDISK.EXE program). The divvy command is used to create divisions within a partition in which the filesystems are created.

To change the hard disk layout, using the cursor keys to move the line labeled "Hard disk setup”. Then press the space bar to bring up the window in Figure 0-4.

Figure 0-4 FreeSCO Installation - Harddisk Setup

After you partition the disk, the system asks what type of disk scan to select. Here, the system will check for problems on the disk. You have two characteristics to choose from. First, you are given the choice between a Thorough and a Quick scan. As one would guess, a thorough scan takes longer than a quick scan—several times longer. However, it is more reliable since the data is read and written more often.

You also choose between a destructive and nondestructive scan. A nondestructive scan reads the data first and then writes back whatever was there originally. A destructive scan writes a known pattern of bytes on the disk first and then reads it. This is obviously destructive because whatever was on that track is overwritten by this pattern. This is more reliable because you always know what the data is supposed to be. Assume the track is not “bad” just “flaky”; that is, only sometimes it is read incorrectly. With a nondestructive scan, you could have read in corrupt data if you write it back and read it again. You don’t know what is correct.

The moral? If there is any question about the integrity of the hard disk, then do a thorough, destructive scan. I say it three times: Destructive means destructive. Destructive means destructive. Destructive means destructive. I have had a number of calls from customers who did a thorough, destructive scan of the complete hard disk, only to find the data on the second filesystem (which they had hoped to preserve across the installation) was gone. Their interpretation of destructive was anything from, “destroying the bad tracks” to”I’m not a techie. How should I know?”

If badtrk finds a problem in the first few tracks of the partition, you are returned to fdisk, so you can repartition the disk around these bad spots. If you have an IDE drive and it appears that your hard disk is full of bad tracks, it probably isn't. Instead, the hard disk parameters might be off, so the system is having trouble accessing the hard disk. You will have to restart the installation and ensure that the system has the correct hard disk parameters. (I specifically mention IDE as I have never seen this happen on a SCSI drive.)

When badtrk finishes, you are prompted for the number of entries to put in the badtrk table. Always put in as many as are recommended, if not more. If sometime in the future your disk develops problems and you need a lot of entries in the table, it can get filled up. Once it’s full, there is nothing to do with additional bad tracks. The only solution is to reinstall. To calculate the amount of space lost, multiply the number of entries in the badtrk table by the sectors per track, then by 512 bytes per sector.

If you are planning to have UNIX take up the entire disk, then leave the option as "UNIX Only”. If this is a new disk or you want to change the partitions on an existing system, you want the "Customize” option. Be careful! Once the system has changed the partition table and begun installing UNIX, there is usually no way to get you other systems back. Therefore, if you choose the "Customize” option and change the partition sizes, you will either have to install the other system from scratch or restore from backups.

For existing systems that you want to leave alone, the Interactive fdisk/divvy option is the best. Here, you can leave the partitions alone and simply configure the divisions/filesystem on the UNIX partition.

My suggestion is that you simply accept the system defaults. The system will create three divisions. The boot division will contain the files and program necessary to boot your system. This is created in the first division (division 0). In division 1, the system creates your swap space. The swap space is used as sort of a temporary holding area when you start running out of physically memory (For details, see chapter 5 of the first book "The Operating System and its Environment.”) This should be at least the same size as the amount of RAM you have. If you have 16Mb or less and plan to run a lot of graphical programs, the swap space should be closer to twice the site of RAM.

In division 2, the system creates the root filesystem, which take up almost all of the remain space in the partition. (The rest is used for housekeeping purposes.)

Depending on what options you previously selected and whether or not there are already any filesystems, you may be asked if you want to preserve the layout of the divisions. If you say "no” the system will decide on some decent default. You may then also be asked if you want a separate /u filesystem. This is a good idea if you will have a lot data on your system. It is easier to backup and is safer if your data is in a separate filesystem.

During the installation it is the divvy program that divides the partition into divisions and then calls mkfs to create the filesystems on those divisions. Although there are eight entries in the division table, the last one (division 7) is reserved and is used to reference the entire partition. If you have a large enough disk, division 6 might be reserved as well. This is the