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PC Historian Finds Puzzling Game Diskette Image

ScuttleMonkey posted about 6 years ago | from the golden-age-of-programming dept.

Classic Games (Games) 232

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.

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Tiltowait (-1, Offtopic)

Anonymous Coward | about 6 years ago | (#25195269)

Tiltowait

Re:Tiltowait (-1, Offtopic)

Anonymous Coward | about 6 years ago | (#25195549)

AC needs Kadorto now!

Re:Tiltowait (4, Funny)

argent (18001) | about 6 years ago | (#25196001)

That was the first game that I pirated... after I bought it.

The copy protection was so messed up that the only way I could get a copy of the game that was reliable was a cracked copy. But I didn't want a pirated diskette, so I had the cracked copy written over the original gold-labelled floppy.

Hybrid disks - not a novel idea after all! (2, Insightful)

Drakkenmensch (1255800) | about 6 years ago | (#25195283)

*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! (5, Insightful)

Hatta (162192) | about 6 years ago | (#25195759)

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! (4, Interesting)

Feanturi (99866) | about 6 years ago | (#25195843)

It's also shockingly cool because my understanding of C64 vs. IBM formatting indicates that the read/write method is entirely different between the two, making it physically impossible for one machine to run emulation to extract info from a drive of the other.

Re:Hybrid disks - not a novel idea after all! (1)

Amouth (879122) | about 6 years ago | (#25196077)

yeap.. and this is why this is "new for nerds" someone spent some time on this.

i would love to know how they went about it - seems like it would be an intresting read

Re:Hybrid disks - not a novel idea after all! (5, Interesting)

blueg3 (192743) | about 6 years ago | (#25195997)

The "Macintosh-format" CDs don't use ISO, they actually use HFS/HFS+. The dual-format disks actually contain an ISO and an HFS partition, but they're engineered so that they share data. You can have ISO-only files, HFS-only files, and shared files; the shared files are only stored once. The ISO partition is used to store data for windows; the HFS partition is used to store data for Mac OS.

The interesting thing about those disks isn't that they're formatted to have two different filesystems on them -- by the time the dual-format CDs were around, putting two partitions on a disk was no big shocker. The interesting part was that they were designed to have two partitions own the same data.

Compare with the disk mentioned in the article. It sounds like the data for the IBM and C64 are entirely separate. The interesting feature is making what is essentially a two-partition disk out of a disk that's designed to be single-partition.

Re:Hybrid disks - not a novel idea after all! (4, Interesting)

Otto (17870) | about 6 years ago | (#25196237)

You think that's neat... This was back several years before XP came out, but I once found a 700 MB image for a CD that had installations for like 15 different versions of Windows, from 95 to 98 to NT4, all on the same disc. Including all the Pro and Server and other versions and everything else.

Basically somebody had sat down and ran a big comparison on all these to find the shared files, then engineered a disc to have all these different partitions own that shared data, allowing for installation of any of them. Then they went a step further and wrote a boot sector to let you boot any of those partitions via a simple text choice at boot time. The result was a single disc that could install any version of Windows that was available at the time.

Had that disc for years, came in extremely handy.

Re:Hybrid disks - not a novel idea after all! (2, Funny)

billcopc (196330) | about 6 years ago | (#25196393)

So that person's claim to fame was using ISOBuster to save an "optimized" ISO ?

Wow.

No really, I'm impressed. I mean, it took some serious cojones to actually click that checkbox.

Re:Hybrid disks - not a novel idea after all! (0)

Otto (17870) | about 6 years ago | (#25196603)

Never heard of "ISOBuster", nor can I find any reference of it being about to do anything like WTF you are talking about via Google.

So.. [citation needed].

They might be multi-format (1)

Sycraft-fu (314770) | about 6 years ago | (#25196037)

CDs have various formats they can have written on them, and there is a Mac specific one. However, there isn't anything that neat about it since it is all part of the spec and you just tell your burner software how to handle it. I don't know all the details of all the different things you can do but mixing all sorts of different data modes on a CD is no big deal. Same kind of thing as mixed audio/data CDs.

Re:Hybrid disks - not a novel idea after all! (1)

Yvan256 (722131) | about 6 years ago | (#25195805)

Your Blizzard "game disks" are CDs or DVDs, not diskettes. Most software CDs and DVDs these days use the same file system, no matter what the target operating system is.

Re:Hybrid disks - not a novel idea after all! (2, Informative)

blueg3 (192743) | about 6 years ago | (#25196055)

See my response above -- "Mac/PC" hybrid disks actually use two different filesystems. Macintosh CDs use the HFS/HFS+ filesystem. People took advantage of this to make dual-filesystem hybrid disks. (On the other hand, having two partitions with different filesystems on one disk was old hat by the time data CDs were around.)

In my day, we had to hand format disks (5, Funny)

Anonymous Coward | about 6 years ago | (#25195331)

With a tiny magnet, flipping 1's and 0's.

Re:In my day, we had to hand format disks (5, Funny)

porkchop_d_clown (39923) | about 6 years ago | (#25195371)

You had magnets!?!

We had rub our fingers against piece of sheepskin really fast to build up a static charge and then touch the bits to flip them!

Re:In my day, we had to hand format disks (5, Funny)

JeanBaptiste (537955) | about 6 years ago | (#25195505)

You had fingers!?!

I'm not even going to tell you how we charged our sheepskins.

Re:In my day, we had to hand format disks (4, Funny)

Hurricane78 (562437) | about 6 years ago | (#25196495)

Let me guess... Hillbilly style, from behind? :D

Re:In my day, we had to hand format disks (5, Funny)

Anonymous Coward | about 6 years ago | (#25196541)

And that's the reason there are so few famous female programmers.

Re:In my day, we had to hand format disks (-1, Redundant)

Anonymous Coward | about 6 years ago | (#25195593)

Obligatory xkcd [xkcd.com]

Re:In my day, we had to hand format disks (5, Funny)

Anonymous Coward | about 6 years ago | (#25195379)

you had ones AND zeros? We only had zeroes. We were too poor to afford all those ones. We had to just close our eyes and imagine the ones. When we finally got a few ones, we had to use them sparingly and reuse them, we only had 8 ones between all us kids, and when we wanted to format our disks, we had to format then one byte at a time, then recycle those ones. SUre, you might occasionally get lucky and get to do a few bytes at the same time, but those solid blocks of 255s used to kill us. Spoiled rotten damn rich kid,

Re:In my day, we had to hand format disks (1)

CFBMoo1 (157453) | about 6 years ago | (#25195385)

Ugha... me day me used rock hammer and stone chisel. Had lift disk with legs not back. Ughha... Dump in river ruined disk... buga... damn erosion. ughaaa!

*Beats stick on ground*

Re:In my day, we had to hand format disks (5, Funny)

morgan_greywolf (835522) | about 6 years ago | (#25195405)

Disks? Huh. You kids and your newfangled "disks". Why, in my day, we had paper tape. Except we were too poor to have a tape puncher, so we had to use a pencil! And we were too poor to own a pencil sharpener, so when the pencil broke, we had to use our teeth!

Now get off of my lawn!

Re:In my day, we had to hand format disks (5, Funny)

The Great Mooch (217006) | about 6 years ago | (#25195475)

You kids and your new fangled paper tape. In my day we had to chew the wood into a pulp to make the paper to make the cards we had to use.

Now get off my lawn.

Re:In my day, we had to hand format disks (4, Funny)

DigitAl56K (805623) | about 6 years ago | (#25196185)

You had wood? .. wait, on second thoughts I don't like where this is going ..

Re:In my day, we had to hand format disks (5, Funny)

richie2000 (159732) | about 6 years ago | (#25195481)

You have a lawn? Spoiled brat!

Re:In my day, we had to hand format disks (5, Funny)

Kratisto (1080113) | about 6 years ago | (#25196619)

You have Italics? In *my* day, the only way to show emphasis on the internet was to put asterisks on either side of the word. Do you youngins have any idea how much sarcasm went unnoticed back in the day?

OB: XKCD (0, Funny)

Anonymous Coward | about 6 years ago | (#25195543)

Pussy. I use butterflies.

http://xkcd.com/378/ [xkcd.com]

Re:OB: XKCD (2, Funny)

zippthorne (748122) | about 6 years ago | (#25195933)

Pfft. Real programmers just think really hard, choosing the proper universe such that electrons happen to tunnel at just the right place and time to affect the magnetizer.

Even better ones choose the universe in which the atoms of the proper hard disk spontaneously tunnel into just the right configuration from across spacetime.

Re:OB: XKCD (1)

rickb928 (945187) | about 6 years ago | (#25196101)

Butterflies?

We considered that, but waiting for evolution to process butterflies wasn't an option. We went with Daleks. Time Lords were busy...

Or course, the Daleks caused more trouble than they solved. We shoulda waited for the butterflies after all. Let that be a warning to you .NET types. Don't glom onto the most insanely great thing just cause it's pretty, louder, or has a bigger gun, ok?

Where the fuck is the download link? (0)

Anonymous Coward | about 6 years ago | (#25195369)

n/t

Re:Where the fuck is the download link? (-1, Troll)

Zonk (troll) (1026140) | about 6 years ago | (#25195495)

n/t

Here. [yahoo.com]

Re:Where the fuck is the download link? (0)

Anonymous Coward | about 6 years ago | (#25195969)

i'm all for shock links, but for shits sake, i'm at work. a short 'nsfw' would be nice.

Re:Where the fuck is the download link? (0)

Anonymous Coward | about 6 years ago | (#25196181)

i'm all for shock links, but for shits sake, i'm at work. a short 'nsfw' would be nice.

I was too scared to click- what was it? The end of that Jerry Seinfeld Microsoft advert where Bill G wiggles his backside?

*shudder*

Prior Art! (5, Interesting)

localman57 (1340533) | about 6 years ago | (#25195435)

Wonder how many patents this potentially invalidates?

Not really that hard... (5, Informative)

TBadiuk (14048) | about 6 years ago | (#25195455)

(wow...my first slashdot post in like 5+ years...something I actually can know stuff about! LOL)

I wanted to email Trixter this but couldn't find a contact email.

It's been now about 25 years but I still have parts of the C64 ROM's memorized. There was a time that I knew pretty much what every byte in the 64k(*) of memory was for cold without needing a reference manual. Having said that:

This wouldn't have been all that hard to do by somebody who had intimiate knowledge of *both* IBM and C64 formats I'd imagine. First, I doubt it was done 'by hand' as in a manual sector by sector copy. A program would have been written, using a slave-master 2 drive config, to stream from the source drive to the dest. drive using a list ot sectors/tracks and/or using a simple formula to calc where the tracks should go. You simply would pick areas on the C64 side that you would want reserved for the IBM side and vica versa. Knowing both IBM and C64 MFM structures would allow you to pick "safe" areas for both formats.

Oh, and the directory structure of the C64 did indeed live on track 18. All the other data blocks where chained out as a linked list from the entry in this track.

All that would have been really needed is:

#1) Format the disk for IBM and use whatever areas you need via a streamed block by block copy from Src to Dst.
#2) Noting which tracks are "safe" to use on the C64, simply write a program to format track by track and write the C64 data, streaming again.

Ingenious, but really not that hard at all...

(*) Well, more like ~80k with the shadow RAM near the top of the 64k range...

Ted

Re:Not really that hard... (3, Informative)

Nursie (632944) | about 6 years ago | (#25195707)

I thought C64 floppy drives were notoriously hard to emulate because the drive was programmable and the disc often contained a program made to read its own content?

In which case you could pretty much do what you wanted, loader-program location excepted.

Re:Not really that hard... (5, Interesting)

TBadiuk (14048) | about 6 years ago | (#25195803)

That was the case for heavy-duty copy protection schemes. The idea was that you'd have a small area of the drive with a loader program in the "normal" format and track 18-0 as readable as well so you could do the directory, the rest in your own non-standard format the couldn't be read at all. You'd then do all sorts of wacky code tricks to obscute the loader program itself, but once it loaded, it could deal with the non-standard data blocks/tracks on the disk.

Ted

Re:Not really that hard... (5, Informative)

TBadiuk (14048) | about 6 years ago | (#25195849)

Oops- forgot to add, of course if you didn't do copy-protection at the disk level (as I'm guessing the case is here, hard enough to make it dual format!), this wasn't an issue. You just interwove the data so neither side (C64/IBM) really knew about the other, or cared really. If it wasn't linked via an entry in track 18 the C64/1541 had no business "looking" at a track/block). Not sure what the deal was on the IBM side but I'd guess simular.

Ted

Re:Not really that hard... (4, Informative)

Sloppy (14984) | about 6 years ago | (#25195721)

Knowing both IBM and C64 MFM structures would allow you to pick "safe" areas for both formats.

Poor choice of words, since the C64 (well, the 1541) didn't even use MFM. ;-)

These aren't just two different filesystems; we're talking about two different encoding schemes used on the same medium, on a track-by-track basis.

Not hard? Ok, fine, once you've thought of it, you can do it. Weird and a historical curiosity? You betcha!!

Re:Not really that hard... (5, Interesting)

TBadiuk (14048) | about 6 years ago | (#25195917)

Actually, I butchered a few terms in my post most likely. My brain nearly froze trying to remember the different terminologies (block/sector etc) from back in the day! I haven't done low level disk stuff on any platform since the late 80's. I think I got the meaning across OK hopefully.

Also- I think the encoding was more likely at a lower level then even what you'd consider "track basis". I don't really know the IBM side so I don't know if the interleave would have been same, etc. Again I can visualize what I mean here, but I can't remember the terms anymore for what the "lead in", "gap" etc in the low level bit encoding was called. I think I've blocked out all the programming knowledge I used to have regarding getting the 1541 to do it's voodoo (*shudder*, assembly from hell!).

Ted

Eats Shoots & Leaves (0)

Anonymous Coward | about 6 years ago | (#25196493)

Nit pick-

The improper phrase would have been "Knowing both IBM, and C64, MFM structures would allow..."

As written without commas it does not imply that he is saying "IBM MFM and C64 MFM".

It could have been clarified by writing "both IBM, and C64 MFM, structures would allow..."

Re:Not really that hard... (2, Informative)

multipartmixed (163409) | about 6 years ago | (#25195737)

Nit: The 1541's directory structure lived on track 18, not the C64's.

Track 18 was chosen because it was in the middle. That was the typical way Commodore did it back in the day -- So 4040s, 2031s, 1540s and 1541s had track 18 directories, but 8050s, 8250s, and SFD-1001s had them on track 40.

No idea where the harddrive dirs were, I couldn't afford one.

Re:Not really that hard... (0)

Anonymous Coward | about 6 years ago | (#25195789)

Knowing both IBM and C64 MFM structures would allow you to pick "safe" areas for both formats.

What does MFM decode to here? It can't be Modified Frequency Modulation because only the IBM half of the floppy uses that to encode its bits, the C64 half uses GCR and both parts are completely unreadable on the other drive - you couldn't read or write even a single bit in the "wrong" sectors/tracks without reformatting them to the proper coding scheme.

Re:Not really that hard... (1)

TBadiuk (14048) | about 6 years ago | (#25196029)

GCR - Thank you! That's the acronym I meant! I've been brainwashed by the PC world it seems, whenever I think :bit level media encoding" the letters "MFM" immediately jumps to mind these days...:-(

As for getting them to play nice with each other - just set up the directory so that the C64 has no business ever "looking at" a IBM section (and vica versa). In this case, the entries (files) in track 18 just need to point to only the "good" C64 blocks. The C64/1541 never touched (well,read) any block unless it was in a files chained pointer list. Also, I believe (bit fuzzy here) you have a "free block table" so you could have even marked off all the other areas so you could write to the IBM portions. Well, at least not through the normal SAVE command anyway (ie- mark the disk as full, 0 blocks free).

Ted

Re:Not really that hard... (1)

mattack2 (1165421) | about 6 years ago | (#25196769)

Do you mean that there is a file on the IBM side 'taking up' the space for the C64 side, and vice versa? If so, couldn't you (or someone else) hose the disk by trying to delete that file "to make more space"? Though maybe these weren't even MSDOS disks, and thus had a completely custom filesystem, like lots of software back then.

Re:Not really that hard... (2, Funny)

Anonymous Coward | about 6 years ago | (#25195871)

>It's been now about 25 years but I still have parts of the C64 ROM's memorized.
>There was a time that I knew pretty much what every byte in the 64k(*) of memory was for cold without needing a reference manual.

I have SYS 64738 that part of my memory a long time ago.

Re:Not really that hard... (1)

TBadiuk (14048) | about 6 years ago | (#25195959)

I could have sworn I saw all the bits on my LCD all shift over about 0.25" for a second, then go to normal as read that! LOL

Ted

Re:Not really that hard... (1)

snarfies (115214) | about 6 years ago | (#25196247)

The C64's 5.25 drives (1541, 1571) didn't use MFM - they used GCR. Only their 3.5 drives (1581) used MFM.

Re:Not really that hard... (1)

multipartmixed (163409) | about 6 years ago | (#25196473)

No. The 1571 could do either GCR or MFM. MFM support was added so that CP/M programs from Osbourne, Kaypro, Epson and IBM could be read on the C=128.

Re:Not really that hard... (1)

snarfies (115214) | about 6 years ago | (#25196569)

I stand corrected, but I very much doubt that this game was written for use only on a 1571 drive - the majority of Commodore owners had a 1541.

Re:Not really that hard... (0)

Anonymous Coward | about 6 years ago | (#25196483)

(wow...my first slashdot post in like 5+ years...something I actually can know stuff about! LOL)

This is actually not a requirement any longer to post here. Not for posters, editors, or even submitters! And if you get caught telling a fib, you can just say that you heard this from your girlfriend in Canada. :)

Re:Not really that hard... (1)

MBGMorden (803437) | about 6 years ago | (#25196553)

It's been now about 25 years but I still have parts of the C64 ROM's memorized. There was a time that I knew pretty much what every byte in the 64k(*) of memory was for cold without needing a reference manual. Having said that:

Neo: Do you always look at it in code form?
Cipher: Well, you have to. The viewer works for the Ti-99/4a, but there's way too much information to decode the C64.

Re:Not really that hard... (1)

nEoN nOoDlE (27594) | about 6 years ago | (#25196649)

You forgot "Now get off my lawn!"

GNAA (-1, Troll)

Anonymous Coward | about 6 years ago | (#25195519)

http://goat.cx/ [goat.cx]

I seem to recall that there were others like this. (0)

Anonymous Coward | about 6 years ago | (#25195521)

Back in my Atari days, I seem to recall there being some games that had Atari and C64 versions on the same side of a disk even though the two formats were incompatible. Couldn't tell you which ones anymore, though.

Atari 800/C64 disks (2, Informative)

logicassasin (318009) | about 6 years ago | (#25195891)

If memory serves me right, the disks you're thinking of were from Mastertronic or possibly Epyx (specifically, World Championship Karate, the only game by Epyx I had on floppy). There's a chance that it could have been one of Datasoft's games as well.

Re:I seem to recall that there were others like th (0)

Anonymous Coward | about 6 years ago | (#25195895)

I remember one of them being some sort of karate game. I'm thinking it was this one:
http://www.mobygames.com/game/atari-8-bit/ninja_/screenshots [mobygames.com]

I recall running the sector editor on the disk and finding out that if I did a copy of just the sectors the Atari would read onto a new disk, the game would work. The standard Atari DOS copy would fail because it would hit bad sectors (the C64 ones).

There were a few hybrid formats around in the 80s (5, Interesting)

FromellaSlob (813394) | about 6 years ago | (#25195523)

This does look like a very early example, but the technique is not as novel and amazing as the article makes out.

For example, in the UK around 1989 there was a magazine for Atari ST and Amiga users called "ST/Amiga Format" that used a hybrid format on 3.5" coverdisks. The ST used a PC-like 720MB format, whereas the Amiga had its own filesystem that fitted 880MB on the same disk. The hybrid disks weren't flippable, they were read double-sided on both systems and just marked the part of the disk used for the other filesystem as bad.

Re:There were a few hybrid formats around in the 8 (0)

Anonymous Coward | about 6 years ago | (#25195597)

1989... 720MB format... 880MB...

WOW

Re:There were a few hybrid formats around in the 8 (2, Funny)

Yvan256 (722131) | about 6 years ago | (#25195839)

Not only that, but on a 3.5" floppy too!

Re:There were a few hybrid formats around in the 8 (1)

niklask (1073774) | about 6 years ago | (#25196013)

Impressive indeed! This also reminds me when I took a Pascal class in high school. We didn't do as much programming as fooling around since our teacher was a total geek too. A friend of mine was paying around with a floppy disk and all of a sudden DOS would report it as several GB. Of course, all data stored on it was corrupted.

Re:There were a few hybrid formats around in the 8 (3, Funny)

FromellaSlob (813394) | about 6 years ago | (#25195853)

LOL, ok that KB, not MB.

Re:There were a few hybrid formats around in the 8 (0)

Anonymous Coward | about 6 years ago | (#25196135)

The ST used a PC-like 720MB format, whereas the Amiga had its own filesystem that fitted 880MB on the same disk.

MB might not be the units you're looking for here...

Re:There were a few hybrid formats around in the 8 (0)

Anonymous Coward | about 6 years ago | (#25196209)

I think you meant KB!

Re:There were a few hybrid formats around in the 8 (1)

cream wobbly (1102689) | about 6 years ago | (#25196369)

Not novel and amazing?

It's novel, because the C64 predates the Amiga and ST by a few years, and this technique certainly predates 1989.

It's amazing, because of the way it interleaves sectors for each "competing" format. ST/Amiga disks didn't interleave the two formats.

ST/Amiga Format (5, Informative)

Ford Prefect (8777) | about 6 years ago | (#25195533)

The short-lived, dual-format ST/Amiga Format [wikipedia.org] magazine from the late 1980s also had an appropriately dual-format cover-disk - somehow combining the apparently wildly-incompatible ST and Amiga floppy disk formats.

I've no idea how it was done (although the fact that many STs had single-sided floppy drives may have had something to do with it) - and while it could have been extremely useful to publish games in such a manner at the time, I don't know that was ever done either.

I get the impression that there was a lot of deep magic involved in these enhanced disk formats, copy protection systems and so on. I'm sure the name Rob Northen [reversers.net] appeared on the front of a later ST Format cover disk - as the supplier of the fancy files-limited-to-particular-sides-of-disk format used to not deprive single-sided drive owners the contents of the entire double-sided disk...

Re:ST/Amiga Format (0)

Anonymous Coward | about 6 years ago | (#25195835)

The Amiga could simply read the ST diskettes. It was a very flexible diskette drive. Computer clubs of the day would line up their Amigas running xcopy in nibble mode, and copy software for all sorts of other platforms. You'd get ST fanboys telling everyone how crap the Amiga was while it was copying their games for them.

Re:ST/Amiga Format (1)

digitalhermit (113459) | about 6 years ago | (#25195865)

The amazing little floppy.. hehe..

Speaking of drives, do you recall the SpectreGCR and the Twister format? One of the Elders at the time (Dave Small) had written a program that re-worked the track/sector format. It skewed the sectors on the the disk so that as the read head moved from track to track it was quicker to get to the next sector number... The Spectre GCR was a hardware device that allowed the Atari ST drives to read the Macintosh disk format.

There was no difference, iirc, between an ST and MS-DOS disk except for some filesystem information. So MS-DOS disks could be read with the appropriate software.

Re:ST/Amiga Format (1)

Chris Pimlott (16212) | about 6 years ago | (#25196643)

One of the Elders at the time (Dave Small) had written a program that re-worked the track/sector format. It skewed the sectors on the the disk so that as the read head moved from track to track it was quicker to get to the next sector number...

I remember non-standard DOS formatters that used that trick, and others that managed to squeeze a few hundred more K out of the standard 1.44mb floppy.

Re:ST/Amiga Format (0)

Anonymous Coward | about 6 years ago | (#25196501)

Yup, Rob Northen was single-handedly responsible for ST/Amiga Format's coverdisk, and a good 80% of most of the other exotic copy-protections on the ST and Amiga. My own Syncro Express (an early, somewhat dodgy, Datel Designs bona fide hardware hack), Knife-ST and MonSTer was probably responsible for copying quite a few of them, too. ;-)

I particularly enjoyed Wayne Smithson's "Anarchy", which was filled from beginning to end with amusing messages and dares from Rob, from the bootsector onwards, as the format got ever more exotic (the game itself was no more than 100K - the rest of the disk was essentially filled with hidden messages that the game didn't even need and Rob apparently had put there entirely for shits and giggles).

I remember when the two magazines split, too, quite largely because of the increasing (legendary) rivalry between the Amiga and ST.

I remember ST Format Cover Disk #1 (with the Bloodwych demo on), too. Not all STs had double-sided drives, and it interleaved each track per side on a double-sided format by default so a single-sided drive couldn't read a double-sided disk at all. So Rob came up with a simple solution; a single-sided format on each side, and a program if you had a double-sided drive that literally swapped the data on sides 1 and 2, essentially flipping the disk for you (which was impossible by hand in a 3.5" floppy without surgery, of course!). The later ones were, indeed, cleverer, and simply allocated all the files and structures onto every other track and formatted the FAT especially so that everything inside the SIDE_2 folder was, in actual fact, on side 2, and you could read the disk fine in a single-sided drive, no daring side-swapping program necessary.

After a while, they didn't bother and just assumed that anyone who still had a single-sided drive in their STF/STFM would have had to get an external double-sided drive because it'd probably conked out by the 3-year mark. :-)

Ah, memories... what have we got now? Weak sectors? Twin sectors? Twin-seek time measurement? Lame-ass rootkits with interpreted self-modifying bytecode callouts? There's nothing new under the sun, but they sure don't make 'em like they used to.

Part of me's glad of that, too. Over twenty years, and more people are copying games than ever before, and the copy protection is still on occasion so awful it encourages people to get the protection-free, 100% working crack. You'd think more of the industry would have learned that they seemed to have survived all that piracy OK to be as big as the movies, so why worry?! :-)

Just more corruption on the 8088 ... (2, Funny)

DigitalDreg (206095) | about 6 years ago | (#25195535)

It's just another case of corruption on an 8088 ;-)

(If you know Trixter, then you know what I'm talking about ... http://www.oldskool.org/pc/8088_Corruption )

Interesting (0, Redundant)

AndGodSed (968378) | about 6 years ago | (#25195539)

What tickles me is the "hand-formatted" part. How was that done?

well... off to rtfa....

Re:Interesting (1)

Yvan256 (722131) | about 6 years ago | (#25195859)

Answer: with a magnetized needle and a very steady hand.

Next question?

Re:Interesting (1)

Amouth (879122) | about 6 years ago | (#25196311)

it was done with butterflies

http://xkcd.com/378/ [xkcd.com]

I thought something different... (1, Funny)

iCeSkUuBe (796431) | about 6 years ago | (#25195553)

I clicked on the story thinking he had found some kind of strange Goatse image embedded in the disk. I was very disappointed.

Re:I thought something different... (2, Funny)

HTH NE1 (675604) | about 6 years ago | (#25196387)

I clicked on the story thinking he had found some kind of strange Goatse image embedded in the disk. I was very disappointed.

Thank you for that. I'll never be able to look at the spindle hole of an 8" or 5.25" disk the same way again.

Floppy Records! (5, Interesting)

qwertphobia (825473) | about 6 years ago | (#25195557)

For some reason it reminds me of the floppy records that came inside magazines, when I was a kid. We would transfer the audio from the record to a cassette, then load the cassette into the computer.

Nobody even whispered, because we were convinced the least bit of sound would get mixed in and corrupted the whole thing. Same goes for acoustic-couple modems, except it really worked that way sometimes. Too much background noise and you'd lose carrier.

Ahhh.. the good old days.

Re:Floppy Records! (1)

British (51765) | about 6 years ago | (#25196165)

I have a 45 single from a new wave band(MainFrame). The B-side doesn't contain a song, but a program, in 3 different versions for some UK computers. Pretty slick. There's a whole web page devoted to cassette programs stuck on Vinyl. I think even The Stranglers did it on a release.

Re:Floppy Records! (1)

cream wobbly (1102689) | about 6 years ago | (#25196449)

"Flexidiscs".

Also reminds me of BASICODE [wikipedia.org] .

Re:Floppy Records! (1)

thermian (1267986) | about 6 years ago | (#25196499)

I have a cassette of spectrum games, and the accompanying book in a plastic case, from a magazine in 1984. PC Format I believe, the box isn't to hand right now.

The magazine is still around, I keep wondering if I should post it to them.

Anyone remember audio+data CDs? (1)

davidwr (791652) | about 6 years ago | (#25195639)

At a trade show in the '80s someone had a Macintosh CD that had audio tracks following. There was nothing magical about this, it was part of the standard.

But it was uncommon. Maybe people didn't like getting random noise when they played the first track in their audio cd player.

Re:Anyone remember audio+data CDs? (1)

Nursie (632944) | about 6 years ago | (#25195817)

Umm, they're still quite common. Lots of music is put out with extra stuff (video or DRM) on data tracks at the end. Usually this uses the CD extra format which puts data at the end in a separate (but linked) session.

The CDROM + audio thing has audio starting with track 2 and is good , but not quite as good because if you put it into a CD player it'll try to play the first track as music and make bad noises.

Re:Anyone remember audio+data CDs? (1)

Stoutlimb (143245) | about 6 years ago | (#25196351)

The grandparent poster must not be used to store bought music media. I sure haven't used any of that obsolete stuff since I discovered mp3's in the 90's. His unfamiliarity with that old format is perfectly understandable.

Re:Anyone remember audio+data CDs? (1)

Penguinoflight (517245) | about 6 years ago | (#25195833)

It really wasn't that uncommon, Microsoft studios did the same thing in the late 1990s with Outwars and the original Age of Empires as well as the expansion pack. Earlier games used this technique to allow for less cpu overhead while playing music, typically the sound was just sent though the cd-in connector.

Re:Anyone remember audio+data CDs? (1)

W. Justice Black (11445) | about 6 years ago | (#25195927)

You used to see this a lot on computer games--one track with code, the others with background music. The game would load and then just tell the audio bits of the CD player to play the BGM tracks. This kept the CPU from having to deal with BGM, and you get CD-quality audio...

Re:Anyone remember audio+data CDs? (1)

drakono (1339167) | about 6 years ago | (#25195929)

Not that uncommon. I remember playing the background music from many of my game discs in a CD player.

Re:Anyone remember audio+data CDs? (1)

Tawnos (1030370) | about 6 years ago | (#25196587)

Quake 2 and Half Life both had excellent soundtracks to listen to independent of the game.

Re:Anyone remember audio+data CDs? (3, Insightful)

WK2 (1072560) | about 6 years ago | (#25196593)

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.

Yawn..... (-1, Troll)

jag7720 (685739) | about 6 years ago | (#25195667)

Yawn.....

Re:Yawn..... (2, Insightful)

poopdeville (841677) | about 6 years ago | (#25196739)

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

Probably the coolest thing ever! (5, Informative)

Bananenrepublik (49759) | about 6 years ago | (#25195699)

This is a cool hack. From what it looks like, this is possible because DOS put the boot sector and the root directory in the beginning of the disk, whereas the C64 made the sane choice of putting it in the middle (think about it, this minimizes seek times). Now the directory (or, more precisely, the File Allocation Table (=FAT)) contains information on so-called bad blocks, i.e. blocks that the OS shouldn't write to because they were known to be bad. If you label the blocks that you put the C64 data into as bad blocks, then DOS is not going to overwrite the C64 data. Now you do the same in the C64 FS and bang -- double OS format created. And it's read/write!

I wonder if someone managed to format a disk such that one was also able to share the data space between the different OSs?

Not the first "double format" image (3, Interesting)

Megane (129182) | about 6 years ago | (#25195795)

This one is relatively easy to do, since DOS uses track 0 to find the directory, and the C64 keeps the directory on a middle track. Even better, the whole second side of the disk could be formatted for PC sectors. But you do have to put the disk through two duplicators, one for the PC sectors, and another for the C64 sectors. (Nowadays this could be done with a Catweasel or similar disk controller that deals with times between transitions.)

This is pretty impressive, but it only needs one format per track. There have been cases where the same track was in multiple formats. The TRS-80 Model I booted from a single-density T0S0, while the Model III booted from a double-density T0S0. There were autoboot games which formatted sectors on track 0 in both single and double density.

As I heard it, the first part of the trick is that the Model I switched density by having both types of disk controller chips. (I don't know details of how the III did it) The second part of the trick is that you start one of the FDC chips formatting a track, then interrupt it partway through. Then you start the other FDC formatting the rest of the track. Presto, you have a track with sectors in both densities! You don't need any other data on track zero, as the boot sectors were customized to boot from the rest of the disk in single density, which both a M3 and an standard single-density M1 could read.

Re:Not the first "double format" image (1)

HTH NE1 (675604) | about 6 years ago | (#25196583)

I also theorized about this as a kid. It's easy when the platforms you want it to work with look at different places for their initial data, and easier if you can direct them to unusual places for subsequent data.

But if you have two systems with different processors both going to the same track and sector for their first data, it becomes an exercise in how to write machine code that both systems can execute and neither of them crash running. A matter of finding safe bytes that do nothing of consequence on one platform but becomes an unconditional branch case on the other so you can split the boot block in half.

And as long as your disk is write protected, you don't need to worry about maintaining two sets of sector allocation tables, or even if they overlap each other. To make one of them writable could be done. To do both would require either teaching each OS how to allocate for the other or sync them on reboot.

Assuming of course there are no Magic Numbers in a common spot to foil any such an attempt, or just completely different formatting methods. E.g. TiVos use a different magic number in their otherwise standard Macintosh partition table to foil trivial access by a Mac to their Ext3 partitions (video is stored in a proprietary filesystem), and earlier models also being byteswapped.

If I really set myself down to do it, I could probably create a 5.25" disk that would boot into ProDOS on 65c02 and 65c816 Apple II machines and into DOS 3.3 on 6502 Apple II machines.

Re:Not the first "double format" image (1)

clone53421 (1310749) | about 6 years ago | (#25196773)

Incidentally, did you know that "<!-- ", in 80x86 assembly, is CMP AL,21, SUB AX,202D? Gives a new (or should I say old) meaning to ".com"...

That is just... (0, Offtopic)

labmonkey09 (992534) | about 6 years ago | (#25195941)

...Awesome.

hey slashdot readers (-1, Offtopic)

Anonymous Coward | about 6 years ago | (#25195957)

you're a bunch of fags!

the good old days of 40/80 floppies. (1)

gtoal (1292978) | about 6 years ago | (#25196435)

We used to do stuff similar to this at Acorn in the 80's, both for multi-system and for the same system but with both 40 and 80 track drives. I vaguely remember that one key feature was that one system numbered tracks from 1 upwards and another from 0 upwards, allowing for two separate directories. There were a lot of tricks that I've forgotten now. You could sometimes fit more than 80 tracks on a floppy. And then there was the 9 vs 10 sectors per track issue. I was only peripherally involved in this area, but we had a couple of guys who knew it inside out. In fact our guys who wrote our disk protection mechanisms were damn good at breaking everyone else's too :-) I remember tricks with using different FDC controllers and even at one point sticking pins into floppies at exactly the right spot to force a hard error on a sector...

Starglider 2 (2, Informative)

Saffaya (702234) | about 6 years ago | (#25196509)

This game used a custom hybrid format so the same game disk worked on both ATARI ST and AMIGA.

http://en.wikipedia.org/wiki/Starglider_2 [wikipedia.org]

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