[Info-vax] Backup TK50 tapes

[Stephen Hoffman]

On 2013-02-23 20:46:30 +0000, supervinx said:

> Il Sat, 23 Feb 2013 13:39:34 -0500, Stephen Hoffman ha scritto:
> 
>> On 2013-02-23 17:41:38 +0000, supervinx said:
>> 
>>> Well, let's see again what I've understood...
>> 
>> 0) No one willing uses tape boot.
>> 
> Hmmm ... so why do boot tapes exist ?

Because the Internet and bootstraps from remote servers didn't exist?

... Because USB disks didn't exist?

... Or because DVD or CD optical media didn't exist?    (CD also 
replaced 8 track cassettes, cassette audio tapes, and vinyl records.  
But I digress.)

... InfoServer wasn't and never became ubiquitous, and early VAX/VMS 
didn't have satellite boot capabilities...

Because computing was different in the 1970s?   We don't have to toggle 
addresses into the front panel switches anymore.  Yeah, I know, that 
wasn't VAX-11.  That was some of the PDP-11 boxes back then, but I 
digress.

Because the best of the available options into the 1980s was 9-track 
magtape, TU58 cartridge "disks", an RX01 floppies, or (more expensive) 
disk cartridges, or a few other hunks of roughly-contemporary hardware?

Back then, magtape was capacious, easily shipped around, relatively 
resistent to damage, and cheap.

This stuff got started back in the VAX era with the TU58 DECtape II 
"disks" (small, slow "disk") and RX01 floppy disks (small, slow), and 
magtape (cacious, slow), but 9-track magtapes required a large and 
expensive widget, later reduced to a less-large and less expensive 
TU80, then to a less-large and less-expensive) TSZ07 or TK50 and DLT 
and some other devices, yes with a sojourn into RL02 and RC25 and RA60 
disks of which the media distro disks for a while but also pricy 
options.

Given tape boot existed for the big VAX systems, adding other tape 
cartridges to the list was incremental work.  Maintaining the whole 
mess was another matter.  As was waiting for the tape to boot and work.

Since you're seeking knowledge, consider booting standalone from TU58.  
 The wait can be... exquisite.   At the tail end of the support for 
that stuff, there were five volumes required IIRC.  Or better, consider 
what's involved with a boot from TU58 on a VAX-11/725 or VAX-11/730, 
which means waiting for the console TU58, too...  At least with the 
VAX-11/725, you might scrounge RC25 media.  (The RC25 Aztec certainly 
helped ensure mount verification worked.  But I digress.)  All of that 
stuff got retired, too.

> I know that booting from TK50 takes more than an hour ...

TK50 was less than glacial, less than huge, less than scarce, and less 
constrained than earlier media.  With one hunk of media, you didn't 
have to swap cartridges, too.

> But for an historical purpose I'll save those tapes.

Everybody collects something.  Have at.


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