tape drives

[Roy J. Tellason]

On Thursday 24 April 2008 17:34, Chuck Guzis wrote:
> > Date: Thu, 24 Apr 2008 14:20:17 -0400
> > From: "Roy J. Tellason"
> >
> > I saw some conversation going by in here recently about Exabyte drives,
> > only the numbers don't sound anything like what I have,  which is marked
> > "Model: HH CTS".  There are all sorts of other numbers on there,  for
> > various aspects of it.
>
> Most Exabyte drives have model numbers of the form 8xxx, from 8000 to
> 8900, then the "Mammoth" models.  The basic early 8200 will hold
> about 2.1G on a standard 8mm tape.  Later models require different
> tapes to take advantage of larger capacities.
>
> Quality of the drives are all over the place, from the built-like-a-
> brick-outhouse 8200 and 8500 to the cheap-hunk-of-plastic 8700.

These were a part of an IBM box,  SSA?  Something like that.  LOTS of hard 
drives in there,  and some sort of a serial link (loop?) to the computer(s).

> > I'm told that these hold 20G on a tape.  The guy I got 'em from
> > unfortunately doesn't have any tapes to go along with them.  One of those
> > tapes would back up pretty much of what I have on my LAN here,  or whole
> > machines,  as they sit.  I'm guessing that the interface I'll be looking
> > at after I take it off of the current mounting plate will be SCSI-wide,
> > like the CD drives and some of the other stuff I have with it.
>
> I suspect that that's 20G "compressed", which is the equivalent of
> "Chinese electric motor horsepower", i.e. extremely optimistic.

Might be,  might not,  I dunno.

> > Think I can get 'em going under linux?  :-)
>
> Sure--just be certain that the SCSI "flavor" matches what you've got
> on your controller.

The CDROM drives that were in the same box have a pretty standard 68-pin 
connector on the back of 'em that looks to be a good match for some of my 
host adapters.

> The general idea is that any SCSI tape drive that supports the
> standard command set will work with Linux--and probably many other
> platforms.  It's been too long since I did "anybody's SCSI tape
> backup" software, but the only gotchas are packages that use
> nonstandard behavior such as read-after-write or strange varieities
> of tapemarks.  Heck, even the command set for auto-changers is
> standard, being applicable to a little magazine that sits in your
> tape drive to a bunch of robots crusing racks of 1/2" reel-to-reel
> tapes.  At least in theory, you can use anything from a 1/2" reel-to-
> reel drive to a DLT without changing software.

I have a couple of boxes of assorted tapes,  and a changer of some sort would 
sure go a long ways toward removing the tedium out of backing up using those.  
Biggest ones in the bunch though are about 256MB,  if I'm remembering right.

> Most SCSI tape drives feature read-after-write verification, which
> puts them way above the garden variety consumer "floppy tapes", most
> of which were garbage, IMOHO.

Got a few of those drives around too,  and none of them are installed in 
anything.  And tapes to go with 'em.  A Colorado,  and a Conner I think.  
Maybe another one,  I'm not sure.

> While not as good as DLT, 8mm is head-and-shoulders above 4mm DAT as
> concerns reliability.  The bottom of the barrel, IMOHO, was the
> Datasonix Pereos 2.5mm format.

I don't think I've ever run across that one.

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