PC Historian Finds Puzzling Game Diskette Image

This past weekend, Trixter — a self-proclaimed IBM PC historian — picked up some old software for his archive. What he didn't count on was a couple of additional Avantage titles that had never been released into the wild. If this weren't enough of a find, one of these titles provided Trixter with an interesting puzzle: the diskette for Mental Blocks is apparently hand-formatted to work on both C64 and IBM (on a single side, not the "flippy disks" of old). Quite an interesting little piece of history.

Comments

Hybrid disks - not a novel idea after all!

[Drakkenmensch]

*looks at his hybrid Blizzard game disks and smiles* It goes to show that these days, everything new is an old idea!

Re:Hybrid disks - not a novel idea after all!

[Hatta]

Do those disks really use multiple formats, or do they just have Mac and PC binaries available on the same standard ISO file system?

The cool thing here is the media format itself is a hybrid. C64 disks in general are incompatible with DOS disks. But some clever hacker out there figured out a way to build a file system that's valid for both machines. A better analogy would be formatting a disk so that it's ext3 and NTFS *at the same time*.

Re:Hybrid disks - not a novel idea after all!

[Anonymous Coward]

ISOBuster 1.0 came out after Windows XP. The GP was talking about "several years before XP". Probably not an automated process back then.

Now? We have a torrent with all Windows installation CDs. It fits conveniently on two DVD9s.

Re:Hybrid disks - not a novel idea after all!

[Sproggit]

Yes YOU cant see how it can be done, nor can most of us.
Thats why its interesting, because it would require hand crafting two entirely different format types on the same physical medium ... quite a lot more technically difficult than simply using half the tracks for one OS, and the other half for the other.
Please read TFA before attempting to sound insightful.

Re:Hybrid disks - not a novel idea after all!

[banzaikai]

{Sigh}

Okay, folks, here's how you do it...

1) Format using 1541. This will put 174K of data on the bottom side of a DSDD floppy.
2) Manually edit the Block Allocation Map (BAM) to map out ALL tracks/sectors between 0 and 17, leaving track 18 (the BAM) and 19-35 for the 64 program and data (I figure about 82K will be free).
3) Write 64 stuff to disk.
4) Pop disk into PC drive, and either use a custom utility, or just use the FORMAT command specifying that only tracks out to 17 be formatted (FORMAT A: /T:17 /N:9). This allows BOTH sides of the disk to be formatted up to track 17, giving you about 180K to play with. Given the lousy graphics on PCs at the time, this is all you really need. This WILL NOT overwrite any 1541 formatting, since the BAM sits at track 18, and the FAT sits at track 0.
5) write PC stuff to disk.
6) PROFIT!

Another person above wondered if the 1541 had an auto-remap of bad sectors... NOPE. A bad disk/sector would trigger the "headbanger" routine, and the format would fail. In fact, the reason the 1541 was so slow at formatting (about 2 minutes for 174K) was that it would write the track, then read it back to verify, update the BAM, then go back to do the next track. Fastload cartridges bypassed the verify and BAM routines, and could do the same thing in under 30 seconds.

Seriously, am I the only one here who read "Inside 1541 DOS" by Immers and Neufeld?

banzai "Bam-Bam" kai

Re:Anyone remember audio+data CDs?

[WK2]

This is a somewhat common attack vector for Windows. A malware author creates a data/audio CD and then distributes it as an audio CD. If the victim puts it in their CD player, it plays fine*. If they put it into their Linux machine, and then play it like an audio CD it plays fine. But when they put it into their Windows machine, Windows (by default) recognizes the CD as data, and then loads the autorun program, which is a trojan horse.

Sony's rootkit a few years ago did exactly this.

* Some people here are saying that a CD player will attempt to play the data track as audio, and it will be random noise. I have never experienced this from data/audio CDs.

Re:Yawn.....

[poopdeville]

Seriously. If somebody did this today, it would be featured on the daily wtf.