Re: SEA files in GSOS

[mjmahon@aol.com (Michael J. Mahon)]

Jeff Blakeney replied:

>On 09 Sep 2004 23:26:28 GMT, mjmahon@aol.com (Michael J. Mahon) wrote:
>
>>Alistair J Ross wrote:
>>
>>>  I have a SEA file (it's actually the SHRINKIT extractor), which GSOS is
>>>  a text file. I would imagine I just need to alter the file's offset
>>>  with a hex editor, but what is the offset and where is it?
>>>
>>>  I would need to change ASCII -> Executable
>>
>>I would do it by BLOADing the TXT file (specifying TTXT to ProDOS)
>>then BSAVEing it (after prefixing the load address if it isn't already
>>there), but I'm sure others have a better way.
>
>This is a good idea, although you missed the CREATE step,

What CREATE step?  I've never found one necessary for a BSAVE,
and ProDOS allows any (small enough) file to be BLOADed if a
Type specifier is included.

> but in this
>case it isn't quite so straight forward.  GSHK (aka ShrinkIt.GS) v1.1
>is 118,119 bytes long so you can BLOAD the entire thing into memory
>from Applesoft under ProDOS 8.

(No doubt you meant "..so you can't...")

This is, indeed, a critical "detail".  ;-)

>You can do it by using a few commands.  The following assumes that the
>GSHK self extracting archive is named ShrinkIt1.1.SEA (the filename
>for the archive available from A2Central.com's public file library),
>currently has a TXT file type and that the file is in the current
>PREFIX.  Also note that I haven't actually tested this so it might
>need to be tweaked:
>
>RENAME SHRINKIT1.1.SEA, GSHK
>CREATE GSHK.SEA, TS16
>BLOAD GSHK, A$2000, B$0, L$4000, TTXT
>BSAVE GSHK.SEA, A$2000, B$0, L$4000, TS16
>BLOAD GSHK, A$2000, B$4000, L$4000, TTXT
>BSAVE GSHK.SEA, A$2000, B$4000, L$4000, TS16
>BLOAD GSHK, A$2000, B$8000, L$4000, TTXT
>BSAVE GSHK.SEA, A$2000, B$8000, L$4000, TS16
>BLOAD GSHK, A$2000, B$C000, L$4000, TTXT
>BSAVE GSHK.SEA, A$2000, B$C000, L$4000, TS16
>BLOAD GSHK, A$2000, B$10000, L$4000, TTXT
>BSAVE GSHK.SEA, A$2000, B$10000, L$4000, TS16
>BLOAD GSHK, A$2000, B$14000, L$4000, TTXT
>BSAVE GSHK.SEA, A$2000, B$14000, L$4000, TS16
>BLOAD GSHK, A$2000, B$18000, L$4000, TTXT
>BSAVE GSHK.SEA, A$2000, B$18000, L$4000, TS16
>BLOAD GSHK, A$2000, B$1C000, L$D67, TTXT
>BSAVE GSHK.SEA, A$2000, B$1C000, L$D67, TS16
>
>A generic file type changing program could be written entirely in
>Applesoft using this technique but I'll leave that as an exercise for
>others.  :-)

Ah, now I see--it needs to be an S16 file, not just a BIN file...  ;-)
I expected it to be BRUNable, but that would also limit its size.

-michael

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