[Info-vax] Copying VMS SaveSet Under Windows

[Bob Eager]

On Sun, 21 Nov 2010 23:23:08 +0100, Michael Kraemer wrote:

> Bob Eager schrieb:
>> Not really. An ANSI tape consists merely of blocks and tape marks. Some
>> of the blocks are quite small and contain the filenames, labels, etc.,
>> and some contain data. One merely has to read them, store each block at
>> its correct size, and store the mini-blocks that make up the tape
>> marks. ANSI is irrelevant;
> 
> no it's not.
> If I want to read an ANSI tape "properly" this implies I want to lookup
> the files by name or maybe I would copy all files to disk preserving
> name and date, etc. That's the extra information ANSI tapes provide.
> Otherwise I wouldn't use ANSI tapes.
> But for dealing with ANSI tapes this way, you'd have to look closer into
> the header/trailer files, this doesn't come free on most Unices, except
> for those with "ltf" on board.

You're missing the point. You don't need knowledge of the structure of 
the tape at all. You simply replicate the block-level appearance in a 
file, so that SIMH presents it to the simulator in that form. Simulator 
asks for first block on the tape, and it gets the contents of the first 
block, out of the file. It needs *no* knowledge of what's inside; it's 
simply a container. The entity that 'understands' the ANSI structure 
inside the blocks is VMS itself - running in the simulator.

It's no different to a container file emulating (say) an RA81. The system 
(UNIX or whatever) needs no knowledge of what's inside that file.

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