mpd@anomaly.sbs.com (Michael P. Deignan) (12/25/90)
I have a few questions on XENIX tape drives which maybe someone can address. Using an Archive 60mb Internal system, in the /dev directory, we have the following devices defined: crw-rw-rw- 2 root superuser 25, 32 Dec 2 15:28 erct0 crw-rw-rw- 2 root superuser 25, 8 Dec 2 15:28 nrct0 crw-rw-rw- 2 root superuser 25, 24 Dec 2 15:28 nrct2 crw-rw-rw- 2 root superuser 25, 0 Dec 24 14:17 rct0 crw-rw-rw- 2 root superuser 25, 16 Dec 2 15:28 rct2 Now: 1. What is the difference between RCT0 and RCT2? 2. "ERCT0" is a device for a tape system w/ error correction, correct? 3. What are "NRCT#" and why use one of them over the RCT# counterpart? These have been sitting in my mind for awhile and nobody here seems to know the answer. MD -- -- Michael P. Deignan, President -- Small Business Systems, Inc. -- -- Domain: mpd@anomaly.sbs.com -- Box 17220, Esmond, RI 02917 -- -- UUCP: ...uunet!rayssd!anomaly!mpd -- Telebit: +1 401 455 0347 -- -- XENIX Archives: login: xxcp, password: xenix Index: ~/SOFTLIST --
datta@lynx.uucp (Jayadatta N. Seetharamaiah) (12/26/90)
Hardware and Software environment. H/W Multibus - I Intel 80386 and the make is Intel-320. S/W AT&T UNIX Version 5.3.2. The queries: 1. Recently only we moved to UNIX from XENIX. Earlier we used to have an aliased user by name postmaster, whose actual recipient is some one else whose length of the user id doesnot exceed the limited 8 characters. Now on this system I cant have system wide alias ( but using in the file /usr/lib/mailx/mailx.rc with the entry as alias postmaster some name does work locally), but if some sends a mail to vigyan!postmaster it just bounces back instead of going to the user whose name is entered in system wide alias file. 2. In earlier OS namely XENIX, I used to have a parameter by which I used to control the start of the process of uucico for uucp. That was in /etc/default/uucp( the entry was startjob = YES or NO. But in the current version there is no such entry. With this entry if I set it to NO, anyone if uses mail command, the job will just be queued in the spool directory and will not spawn the process uucico. But in this version there is no such function to control the file transfer program uucico. Right now I am controlling in the crontab entry by allowing the system to call only between 2200hrs and 05-30 hrs(In india these are quarter charge hours). But during these hours also anyone sends mail, the process uucico will start immediately in addition with the invoking by cron in the stipulated time. What I want is uucico process should only be started by cron and not by any user. Thanks -Datta
silver@xrtll.uucp (Hi Ho Silver) (12/26/90)
In article <865@anomaly.sbs.com> mpd@anomaly.sbs.com (Michael P. Deignan) writes:
$Now:
$ 1. What is the difference between RCT0 and RCT2?
$ 2. "ERCT0" is a device for a tape system w/ error correction, correct?
$ 3. What are "NRCT#" and why use one of them over the RCT#
$ counterpart?
RTFM. If you have the same manuals as I do (May 16, 1988), look at
TAPE (HW); you'll find out that devices ending in ct0 are QIC24 unit 0,
and those ending in ct2 are QIC11 unit 0. You'll find out for sure that
"Devices beginning with the "e" prefix (for ECC device) support a 2/64 error
recovery scheme. Thus two 512-byte blocks out of every 64 blocks can be bad
and the driver will correct the errors." You'll find out that "Devices
beginning with the "r" prefix, [sic] (for "raw device"), should be used for
most normal tape work, while devices with the "n" prefix, [sic] ("for [sic]
no rewind on hold"), should be used for storing and restoring multiple
files."
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_____________________/ find / -print|xargs cat|compress | SNTFalan@mq.com (Alan Mintz) (12/27/90)
In article <865@anomaly.sbs.com>, mpd@anomaly.sbs.com (Michael P. Deignan) writes: > > I have a few questions on XENIX tape drives which maybe someone can address. > Using an Archive 60mb Internal system, in the /dev directory, we have the > following devices defined: > > crw-rw-rw- 2 root superuser 25, 32 Dec 2 15:28 erct0 > crw-rw-rw- 2 root superuser 25, 8 Dec 2 15:28 nrct0 > crw-rw-rw- 2 root superuser 25, 24 Dec 2 15:28 nrct2 > crw-rw-rw- 2 root superuser 25, 0 Dec 24 14:17 rct0 > crw-rw-rw- 2 root superuser 25, 16 Dec 2 15:28 rct2 > > Now: > > 1. What is the difference between RCT0 and RCT2? rct0 and rct1 refer to QIC24 tapes. rct2 and rct3 refer to QIC11 (whatever that is - anybody ?) > 2. "ERCT0" is a device for a tape system w/ error correction, correct? Yes. > 3. What are "NRCT#" and why use one of them over the RCT# > counterpart? The nrct0 and nrct2 devices do not forceably rewind the tape before (after?) each operation. This allows you to write multiple file system backups on one tape by using the nrct0 device and the "tape" command to write file marks between each backup (see a recent article in either c.u.x.sco or c.u.sysv386 from paulz@sco.com describing the exact procedure). ECC allows a higher recoverable error rate on the tape than the standard encoding scheme (2/64 blocks can be bad, yet recoverable, according to TFM). And a question... If you look at the minors for these devices, it seems that the 8s bit is set for no rewind, the 16s bit is set for QIC11 (as opposed to QIC24), and the 32s bit is set for ECC. This says that the nrct0 and nrct2 devices do NOT (as they are defined) use ECC. Would creating a /dev/enrct0 device with a minor of 40 create a no-rewind ECC device ? -- < Alan H. Mintz | Voice +1 714 980 1034 > < Micro-Quick Systems, Inc. | FAX +1 714 944 3995 > < 10384 Hillside Road | ...!uunet!ahmcs!alan > < Alta Loma, CA 91701 USA | alan@mq.com >