[Info-vax] Backup TK50 tapes

[Johnny Billquist]

On 2013-02-25 15:49, Bob Koehler wrote:
> In article <kgb9r6$mac$2 at tdi.cu.mi.it>, supervinx <nessuno at libero.it> writes:
>> 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 ?
>> I know that booting from TK50 takes more than an hour ...
>> But for an historical purpose I'll save those tapes.
>
>     They existed because there was nothing better at the time.  No one
>     willingly used them because they were painfully slow.  Similated tapes
>     on SIMH are probably several orders of magnitude faster.

Well, tapes were, and still are, a pretty good option for saving data, 
and physically move it around. Having boot tapes is a pretty logical 
extension to that. Besides, booting MicroVMS from RX50 was not really 
any more pleasant than TK50... I think it was something like 23 floppies...

But "orders of magnitude" don't properly describe it. :-)

>     In addition to BACKUP vs. COPY, you need to be aware that SIMH
>     simulated tapes contain SIMH specific overhead.  There are utilities
>     available for makeing these tapes from host disks files, but I've
>     not seen one that I'm happy with.

Not sure what you mean here. If you have a disk file, I don't really see 
any meaningful way of "converting" that into a tape image. Do you mean 
creating a tape image file of an ANSI tape, with that file in there? Or 
converting an existing tape image file into another format?
Or something else...?

	Johnny