Sponsored Content
Top Forums UNIX for Dummies Questions & Answers passthrough devices vs. named devices Post 302202331 by thumper on Wednesday 4th of June 2008 02:41:35 PM
Old 06-04-2008
passthrough devices vs. named devices

I am having trouble understanding the difference between a passthrough device and a named device and when you would use one or the other to access equipment.

As an example, we have a tape library and giving the command
"camcontrol devlist" gives the following output:

akx[22]# camcontrol devlist
<SPECTRA 215 1014> at scbus3 target 3 lun 0 (pass4,ch0)
<SONY SDX-300C 04c7> at scbus3 target 8 lun 0 (pass5,sa0)

The SPECTRA 215 is the tape library the SONY SDX is the tape drive in the library.
To address the tape library a command such as "mtx -f /dev/pass4 command" is used, however to address the tape unit then /dev/sa0 would be used as in
"/sbin/dump -0uaf /dev/sa0 /dev/da4s1e".

Could someone give me a clue on when you address a passthrough device and when you address a named device, or at point me to some documentation that might clear this up?

Thanks
Thumper
 

10 More Discussions You Might Find Interesting

1. HP-UX

HP-UX 10.20 devices

Is it possible to create the CDROM device file for a drive attached to the parallel port? I have a removable CDROM drive (gift - I'm trying not to return it, but may have to anyways) that attaches via parallel port. The only device that I can attach to that hardware address is /dev/c1t0d0_lp, a... (9 Replies)
Discussion started by: LivinFree
9 Replies

2. UNIX for Dummies Questions & Answers

Unix devices

Hi I am trying to determine the access to unix devices. I found the follow access description which I have been told is a symbolic link and is not the actual file. I was also told that all symbolic links will have rwxrwxrwx access. kmem: lrwxrwxrwx 1 root 27 May 28 16:06 /dev/kmem ->... (2 Replies)
Discussion started by: GW01
2 Replies

3. UNIX for Dummies Questions & Answers

printing devices

I am new in unix, and I need to fix a printer, but I don't even know the difference between /dev/ttys printers and lp printers. Can someone explain this to me and tell me how I cancel jobs in both of them? I will appreciate it, thank you. (15 Replies)
Discussion started by: HN19
15 Replies

4. Red Hat

USB Devices

I am trying to get a flash card reader to work with my machine. My question is, are all of my USB ports screwed up? Do I need to buy a seperate USB controller? I does not appear that the onboard USB ports work. In trying to get it to work, I typed cat /proc/scsi/scsi and got this: # cat... (2 Replies)
Discussion started by: davidkretsch
2 Replies

5. Solaris

Meta Devices

I have added a sun storage array from a faiulty server onto a new server and copied the md.conf files etc. I can now access the /dev/md/dsk file systems, but I want to delete some metadevices that do not exist (it still thinks the 0 and 1 (root /var /export) disk are mirrored. How do I do this? (8 Replies)
Discussion started by: ozzmosiz
8 Replies

6. Solaris

what is /devices/pseudo/ ??

Hi all, what does this mean? if then <something> fi here is what i know.. it checks if the specified argument no($devid) in some function call is made into a block device and then proceeds with the execution of the loop. However am not understand what lofi@0:means? also is there... (3 Replies)
Discussion started by: wrapster
3 Replies

7. UNIX for Dummies Questions & Answers

/dev X /devices

Hi folks, I am trying to learn Unix based in Linux... In Linux, in /Dev are files related to cards, mouse, etc.. how about Unix? What is the difference between /Dev and /Devices? Thanks, Fernanda (0 Replies)
Discussion started by: ffpradella
0 Replies

8. HP-UX

list of devices

Hi, I need to rediracte all the names of the devices (only disks) to a file. Thanks:confused: (3 Replies)
Discussion started by: yoavbe
3 Replies

9. Programming

Raw devices in C

Hi guys. what is the benefits of using raw devices in programming? which applications mostly use raw devices? how can i use raw devices in C programs? is there any system calls or library functions? (1 Reply)
Discussion started by: majid.merkava
1 Replies

10. Red Hat

Raw Devices

Can you please modify my script. This script is not working for i in /dev/sdf do /bin/raw /dev/raw/`/bin/basename ${i}` ${i} /bin/sleep 2 /bin/chown orasm:ordba /dev/raw/`/bin/basename ${i}` /bin/chmod 660... (9 Replies)
Discussion started by: karthik9358
9 Replies
TCOPY(1)						    BSD General Commands Manual 						  TCOPY(1)

NAME
tcopy -- copy and/or verify mag tapes SYNOPSIS
tcopy [-cvx] [-s maxblk] [src [dest]] DESCRIPTION
The tcopy utility is designed to copy magnetic tapes. The only assumption made about the tape layout is that there are two sequential EOF marks at the end. By default, the tcopy utility will print information about the sizes of records and files found on the /dev/sa0 tape, or on the tape specified by the src argument. If a destination tape is also specified by the dest argument, a copy of the source tape will be made. The blocking on the destination tape will be identical to that used on the source tape. Copying a tape will yield the same program output as if just printing the sizes. The following options are available: -c Copy src to dest and then verify that the two tapes are identical. -s maxblk Specify a maximum block size, maxblk. -v Given the two tapes src and dest, verify that they are identical. -x Output all informational messages to the standard error instead of the standard output. This option is useful when dest is given as /dev/stdout. SEE ALSO
mt(1), mtio(4) HISTORY
The tcopy command appeared in 4.3BSD. BUGS
Writing an image of a tape to a file does not preserve much more than the raw data. Block size(s) and tape EOF marks are lost which would otherwise be preserved in a tape-to-tape copy. End of data (EOD) is determined by two sequential EOF marks with no data between them. There used to be old systems which typically wrote three EOF's between tape files. The tcopy utility will erroneously stop copying early in this case. When using the copy/verify option -c, tcopy does not rewind the tapes prior to start. A rewind is performed after writing, prior to the ver- ification stage. If one does not start at the beginning-of-tape (BOT) then the comparison may not be of the intended data. BSD
December 20, 2006 BSD
All times are GMT -4. The time now is 10:35 AM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy