difference between /dev/sr0 and
© May 2019 Anthony Lawrence
/dev/scd0

There isn't necessarily any difference at all.

This sometomes comes up because somebody is having trouble accessing a cd - perhaps for reading, but more likely for burning. One device node doesn't work, so they try another.

If a "ls -l" of the two devices gives the same major/minor numbers (see Understanding Unix Devices), the device IS going to behave identically in the kernel, because the major and minor numbers are all that the kernel gets. It picks the driver based on the first number and passes the second number to that driver.

Sure, some silly piece of software might insist that you use some particular name (some serial software does that) but internally, none of that matters.

And what do the minor numbers mean? Whatever the person who wrote the driver wants them to mean. For Linux, there's a good list at https://www.lanana.org/docs/device-list/devices.txt but without documentation like that or source, a minor number doesn't tell you anything.

That is especially true when looking at different operating systems. You might have noticed that tty devices have a major number of "3" on your Ubuntu Linux.On a SCO Unix system, "5" would be used. Different systems will use different schemes.

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2 comments

Sat Mar 20 06:52:47 2010: 8244   anonymous




when a cd writing process is going on then which of the file is responsible to interact with scsi drier or how does cdrecord work?





Sat Mar 20 11:39:29 2010: 8245   TonyLawrence




I'm sorry - I do not understand your question. Can you rephrase?

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