Messages in this thread |  | | From | (Thomas Niederreiter) | Subject | Organization of Generic SCSI-Devices? | Date | Thu, 1 Aug 1996 21:49:07 +0200 (MET DST) |
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Hi,
some comments and questions about the scsi-interface of linux.
First of all it is very poor documented (at least in linux/Documents/scsi.txt) and this makes it hard to find all out somebody might want to know. (I know writing documentation is a pain, but perhaps somebody wrote already something that could be included in the kernel source-tree.)
Ok, my questions:
My programm (X-CD-Roast, CD-Writer-Frontend) is using alot of generic scsi-stuff. Recently some people told me that I use the /dev/sga, /dev/sgb.. devices, which are outdated. According to linux/Documentation/devices.txt (in kernel 2.0+) the device-names /dev/sg0, /dev/sg1 ... should be used.
Nevertheless the sg-module itself reports still /dev/sga and so on. This can be changed in line 505 of sg.c. (Changing 'a'+sg_template.dev_noticed to '0'+sg_template.dev_noticed).
But this means that you can only use up to 10 generic scsi-devices.. - or we have to move up to /dev/sg10+. Or like the ttys are doing it by creating a /dev/sga after /dev/sg9... But this would be MORE than confusing to a lot of programms which expect /dev/sga being the first and not the 10th device. What to do? (I know it is not very likely to have more than 9 scsi-devices, but who knows? )
Another question derives from this...How many generic-devices can be handled by the kernel? And how are they mapped if there are multiple scsi-controllers in the system? (first all on controller 1 and then all on controller 2 and so on?)
The device-system itself can handle up to 255 minor-numbers, right? On my RedHat-based system MAKEDEV creates only 8 devices /dev/sga-h .. The german SUSE-Distribution only got devices /dev/sg0-3. (There I noticed the first time the changed sg-numbers)
Can I create myself more sg-devices by incrementing the minor-number? (The device-name itself doesn't really matter in this case).
A lot of questions, I hope I somebody can help me.
Thanx,
Thomas
___ ___ / | \ ___________ | REAL : Thomas Niederreiter: Munich, Germany / ~ \/ _ \_ __ \ | EMAIL : tn@mailserv.rz.fh-muenchen.de \ Y ( <_> ) | \/ | MUD/IRC: Hor/_Hor \___|_ / \____/|__| | \/ All I want is a warm bed and a kind word and unlimited power -- Ashleigh Brilliant
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