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Comment by MrJagil | Hacker News Reader

>Reviewing the disks’ directory listings, the team’s initial excitement on seeing promising filenames like “campbells.pic” and “marilyn1.pic” quickly turned to dismay, when it emerged that the files were stored in a completely unknown file format,

I wonder what format it was...

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Most likely Graphicraft, which was the paint program he used during the Amiga launch.

I found it quite amusing that they describe it as a "completely unknown file format" - it have taken them minutes to identify the paint program used if they actually read any of a number of accounts of the launch prep.

It's described on page 284 onwards of Commodore: The Amiga Years (Brian Bagnall), and many other places. (EDIT2: Note that specific book was not published when the article was written, but a very similar account is present in an older book by the same author - Commodore: The Amiga Years is the second volume of what started as a second edition of his previous account of Commodore)

EDIT: "Graphicraft" is even present in the images in the article..."

The linked PDF is a better read: http://studioforcreativeinquiry.org/public/warhol_amiga_repo...

They mention Graphicraft was unable to load the images unless booted with a particular Kickstart version.

How is that possible?

The version of GraphiCraft used for the demo was not a finished version, and was known to be buggy. Recollections of people involved includes claims that they were terrified when Warhol used the flood fill, for example, because there was a known bug in flood fill that would cause it to fill memory outside the screen bitmap. So it's quite likely that there other bugs too.

As a wild guess, one possible source of problems might be that GraphiCraft might have taken shortcuts in saving that might have e.g. assumed a certain offset into some data structure to copy the palette information from the file to that changed before release, as some of these early programs were known to basically pretty much dump memory straight to file and load it back in straight into some data structure with minimal parsing and validation.

So interestingly that shows the Venus was IFF ILBM, which matches its origin as a demo image for Deluxe Paint rather than GraphiCraft.

The format for most of the others is described as "PLBM", which makes sense as P(L)BM is basically a cruder variation that'd allow dumping the screen/window content to the disc in planar format directly (native for all Amiga on-screen display prior to AGA or graphics cards) with minimal framing, while ILBM interleaves the bitplanes row by row (and can optionally use run-length encoding too), and so needs a bit more finesse.

It's kinda funny how they play up that the person who found this out "specializes in and is world-renowned for hacking and reverse engineering" - if you're remotely familiar with image file formats, it takes about 5 seconds of looking at these files in a hex editor to see that they're an IFF related format, and the chunk names are plain ASCII. I'm sure the person in smart - I'm not disputing that; but they're overplaying how much expertise is required for this.

Both ILBM and P(L)BM are formats you can write a basic decoder for in an hour or two - IFF contains chunk headers and length markers to let you extract each chunk, and you need the palette information and the bitplanes. ILBM also allows for basic run-length encoding. There's no complicated compression or anything else to make it hard.

I wonder how much reverse engineering they actually did before using Graphicraft. Or it could be a embellishing by the author of the piece.

> EDIT: "Graphicraft" is even present in the images in the article..."

But how did they know that before they were able to view the images?

They wouldn't know that - I meant that as confirmation that it was in fact GraphiCraft that was used. They would however know it was GraphiCraft if they read up on the event in advance.

They don't really say very much. The Venus bitmap was a demo picture that shipped with Deluxe Paint (and the one they've published seems to be blank where the header/toolbox would be), and although they credited it to Warhol it doesn't appear he's done much than cut/paste a third eye in.

If these were system disks from a prototype Amiga, then it makes sense that these pictures came from an early version of Deluxe Paint, and that .pic was some intermediate / temporary / memory-dump type format before they adopted the .iff system.

Given the Amiga was quite different display-wise, a description of the file format would probably be quite instructive in terms of whether it was an Amiga-native data structure or something already existent somehow.

He used GraphiCraft for the demo, but of course it's possible he at some point later used DPaint. I do believe the reason GraphiCraft is present in the images, though, is because GraphiCraft early on did in fact use pretty much a memory dump. Several of the early graphics programs in fact didn't store a separate full copy of the bitmaps, but let you draw directly into an window on the screen, and relied on AmigaOS to preserve any sections temporarily covered by other windows.

But DPaint at least let you paint under the title bar.

Later versions of GraphiCraft did use IFF, as Commodore wholly embraced the format once EA released it.

> it doesn't appear he's done much than cut/paste a third eye in.

To be fair, that third eye changes the picture in a very significant way, in artistic terms. Art is not about quantity of effort.

ugh

I mean, it can be. Just might not be tangible effort. Thought, planning is effort. Banksy, for a beaten to death example.

Minor Nit: IFF was released in Jan 85 [0], a few months before Amiga was released and several Amiga guys, including RJ, contributed to the spec. It was baked into the Amiga from the very start.

So Commodore's Graphicraft was probably always using ILBM IFF, maybe with new and pre-release chunk types. :)

I'd be very surprised if they weren't alpha IFF or some such. I'd love to see a hex dump of the start of a file.

[0] http://static.lightwave3d.com/sdk/11-6/html/filefmts/eaiff85...

"IFF" doesn't say all that much, of course, as it's just very basic framing. It's the chunk types that matters.. It does seem the images were in fact PLBM, so very similar to ILBM but "raw" bitplanes instead of interleaving row by row.

It's pretty much a memory dump of the window/screen bitmaps with a bit of extra data in front.

The original Amiga Venus image was created by Avril Harrison (The AH in the lower left corner. She did a lot of awesome work for LucasArts, too.)

http://amiga.lychesis.net/artist/AvrilHarrison/AH_Venus.html

I'm guessing it was either a raw binary dump, or the old (even then obsolete) IFF PLBM format, which preceded the well-known IFF ILBM format. PLBM files were found on the famous EA Kaleidoscope demo disk.

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