[comp.sys.att] 7300/3b1 23Mb Tape Drive: Some Observations

ignatz@chinet.UUCP (Dave Ihnat) (12/15/87)

[The following is in response to queries from a well-known net reader,
 who suggested my humble opinions may be of interest to the net, as
 well.  If so, so be it...here is the salient part of my note to him.
 -DMI]

Now, about the tape drive.  Yes, it's a 23Mb unit; the driver is much like other
System V implementations, in that a device is a file is a device.  That is, yes,
you *can* cpio, tar, cp, cat, od, etc. to/from the device.  "Is it like a
floppy?"  If you mean run mkfs on it, I haven't tried, but I've not seen a
Unix system since v7 (oh, some *very* early 3.0--a BTL internal precursor
to System III--also) allow this.

The only thing I can say that's nice about this thing is that it makes backups
possible, if not comfortable.  It is unconscionably *slow*; I've about 75% of
my 67Mb disk full, and a total backup runs in the neighborhood of 1 1/2-1 3/4
hours.  They provided special backup programs--as usual on the 3b1, a set of
UA windows, plus the underlying commands--but, as usual, they totally screwed
up in the backup/recovery procedures, so I find them useless as is.  (For
example, you've three forms of backup--'full', 'user', and by list.  But the
full isn't--it won't backup installed software from the foundation set.  On
recovery, they expect you to do a re-installation, then recover, ignoring the
possiblity that you may have modified default UA scripts, /bin and /usr/bin
programs, etc.)  Documentation is **totally** at the command level; no driver
ioctl() documentation at all.  In fact, it's a good thing there are example
scripts in the command documentation, because there isn't even a man page
describing the device driver (/dev/rft3.)

As for portability, it uses DC600 tapes.  Period.  Don't try to slip in the
much cheaper DC300 tape cartridge, either--they enforce the DC600 by timing
the retensioning pass (which the driver forces on every tape insertion), and
just going zonk if the time isn't right.  (What a stupid idea; what do they
care if I decide to use twice as many tapes?)  Actually, a partial answer to
that frustrated question may lie in an attempt to make this thing 3B2-
compatible.  The software provided allows multiple volumes/cartridge, in which
case only other 3B1's will know the internal (undocumented) tape format.
However, if you select '3B2 compatible' mode--basically, no 3B1 VTOC, no
multiple vols/cart--they purport the tape may be read by 3B2 tape drivers;
and, presumably, vice versa.  Haven't tested their claims yet.

In all, a pretty miserable showing for $1200; but, for now, it's the only
game in town.  Hope this helps; as/if I get more solid info, I will post
to the net.  This article will probably show up in a while, with some editing.

	Dave Ihnat
	Analysts International Corp.
	ihnp4!homebru!ignatz
---------
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			Dave Ihnat
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