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What's "IBMLZRW.EXE" for?

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  What's "IBMLZRW.EXE" for? Louis Ohland <ohland@charter.net> - 2026-08-01 09:14 -0500
    76/77 is the only appearance Re: What's "IBMLZRW.EXE" for? Louis Ohland <ohland@charter.net> - 2026-08-01 09:29 -0500
      Re: 76/77 is the only appearance Re: What's "IBMLZRW.EXE" for? Louis Ohland <ohland@charter.net> - 2026-08-01 09:31 -0500
        Tentative view of IBMLZRW functions Re: What's "IBMLZRW.EXE" for? Louis Ohland <ohland@charter.net> - 2026-08-02 07:09 -0500

#71493 — What's "IBMLZRW.EXE" for?

While confusing folks about refdisks, I was snuffling about, looking for 
a wide variety of things. SC.EXE versions, DEV129.DGS versions, string 
theory...

Looking through the 9576/9577 Diagnostics diskette,
https://ardent-tool.com/disks/7677diag.zip

  I noticed "IBMLZRW.EXE", and being a file name that I cannot EVER 
remember seeing, it drew me in.

Using a hex editor, the only human readable stuff was sparse:

USAGE: IBMLZRW [/u] [/d]
$Licensed Material - Property of IBM (C) Copyright IBM Corp. 1981, 1993 
All Rights Reserved.IBMLZRW not loaded
$IBMLZRW removed
$IBMLZRW cannot be removed
$IBMLZRW already resident

"LZRW" is a compression technique AFAIK.
http://ross.net/compression/index.html

  The author of LZRW walked away from it after some patents were 
published. Nowadays, with monstrously XBOX HUUGGEE drives and GB of RAM, 
compression is nowhere near as significant as it was.

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#71494 — 76/77 is the only appearance Re: What's "IBMLZRW.EXE" for?

Just took a pass through the other diags disks... The 9576/9577 Diags 
disk seems to be the ONLY refdisk or diags disk to have "IBMLZRW.EXE"

The truth is out there...

Louis Ohland wrote:
> While confusing folks about refdisks, I was snuffling about, looking for 
> a wide variety of things. SC.EXE versions, DEV129.DGS versions, string 
> theory...
> 
> Looking through the 9576/9577 Diagnostics diskette,
> https://ardent-tool.com/disks/7677diag.zip
> 
>   I noticed "IBMLZRW.EXE", and being a file name that I cannot EVER 
> remember seeing, it drew me in.
> 
> Using a hex editor, the only human readable stuff was sparse:
> 
> USAGE: IBMLZRW [/u] [/d]
> $Licensed Material - Property of IBM (C) Copyright IBM Corp. 1981, 1993 
> All Rights Reserved.IBMLZRW not loaded
> $IBMLZRW removed
> $IBMLZRW cannot be removed
> $IBMLZRW already resident
> 
> "LZRW" is a compression technique AFAIK.
> http://ross.net/compression/index.html
> 
>   The author of LZRW walked away from it after some patents were 
> published. Nowadays, with monstrously XBOX HUUGGEE drives and GB of RAM, 
> compression is nowhere near as significant as it was.

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#71495 — Re: 76/77 is the only appearance Re: What's "IBMLZRW.EXE" for?

I wonder if LZRW is for a compressed drive, and does not work on the ROM 
image. Akin to "Stac"

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#71496 — Tentative view of IBMLZRW functions Re: What's "IBMLZRW.EXE" for?

https://forum.vcfed.org/index.php?threads/whats-ibmlzrw-exe-for.1258414/post-1512500

Bloodycactus wrote:

looks more like it provides an interface on int 0x2F and 0x21 (and can 
load like a .sys file).

dont load ibmlzrw, use a tool like (list.com) to look at diags.com, its 
a pile of compressed junk.

now load ibmlzrw, and use list.com to look at diags.com again.....

it basically decompressed a file executed or loaded that has the 
signature. (maybe the EDSY marker).

think of it more like PKLite or LZEXE, but it doesnt put the 
decompression runtime onto each executable, the runtime is provided by 
ibmlzrw.

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