ZSR@PSUVM.BITNET (07/28/87)
Hi there to everyone out there in Atari ST-land or Mac-land (I cross-posted
this to comp.sys.atari.st and comp.sys.mac).
Here's an interesting problem that I'm faced with:
I own and use an Atari ST and have some programs (Publishing Partner,
First Word) that can (one way or another) generate PostScript output.
(No flames, please from those in Mac-land...that's not the problem :-))
The problem is that the only way that I can gain access to a LaserWriter
is through a Macintosh Appletalk network. While it is possible to
transfer the text files to a Macintosh (my roommate's) using a modem,
that will not always be an availible option. Therefore, is there any way
that I can get a Macintosh to read files written by my ST? I know that the
floppy chips are similar, but not exactly the same (or is it the drives?)
I also know that the ST can be kluged to write 800K disks (I read it on the
net somewhere). My question is, can the ST write files that are readable
by the Mac? I don't need the files to *run* on the Mac; I just want to write
a PostScript text file from my ST and be able to read it on a Mac and dump
it to the LaserWriter. I have not been able to get any info on the Mac disk
formats yet, so I don't even know if it is electrically (magnetically?)
possible.
Does anyone in either plane of existance have any ideas on a possible
compromise format? I can program and kluge for the ST, but I have no
tools to program a Mac. What about Magic Sac format? What about an
intermediate format not known to either computer (yet)? Any and all
comments, either E-mailed or posted to comp.sys.atari.st or comp.sys.mac
would be *greatly* appreciated. This is a real puzzle. Thank you...
Christopher D. Johnson
Penn State University
ZSR @ PSUVM.bitnet
daveh@cbmvax.UUCP (Dave Haynie) (07/29/87)
in article <17421ZSR@PSUVM>, ZSR@PSUVM.BITNET says: > Xref: cbmvax comp.sys.atari.st:4520 comp.sys.mac:4957 > > Therefore, is there any way > that I can get a Macintosh to read files written by my ST? I know that the > floppy chips are similar, but not exactly the same (or is it the drives?) > I also know that the ST can be kluged to write 800K disks (I read it on the > net somewhere). My question is, can the ST write files that are readable > by the Mac? Maybe. First of all, the floppy controller chips on the two machines are very different. The ST uses a more traditional controller chip, much the same as the IBM PC world, which is why the ST format is essentially in the "standard" format (kind of funny, since most 3.5" floppies are in Mac format today, as a whole. Though most floppies in general are in IBM format, of which the ST format is basically an 80 track extension of). IBMs and Ataris do things on their floppies pretty straightforward. They format a standard 9 sectors per track for 80 tracks, double sided (though some STs still do single sided), and this can be read with just about any floppy controller. This is all in MFM encoding, which dates back to the CP/M world (at least). The Mac is a bit stranger. It uses a Apple-specific version of an encoding scheme know as GCR, with some additional strangeness. When you think about storing data on a floppy, you should consider the fact that you're dealing with a circular medium. This medium has a maxium bit density that can be written reliably. The thing is that, at a constant angular velocity and data rate, this maximum density is only achieved on the inner track of a floppy, which is the smallest linear space written to. The older Macs realize that, on the outer tracks, there's much more space available, but to write to this, you've got to change something. These Macs change their drive speed as they get to the outer tracks. So with a Mac, you get more tracks written on the outer tracks than the inner tracks. The newer ones (Mac SE, Mac II) do this electronically, not mechanically. But this causes problems for anyone attempting to read this with a non-Mac machine. In passing, I should mention that the 8-bit Commodore disk drives, which also use a form of GCR encoding for their native format, have used the electronic method mentioned since they were originally designed. I should also mention the Amiga here, 'cause it does thing a different way. Basically, on a normal PC style drive, you get a request to read/write a sector, then you read/write it. This requires sectors to be spaced apart from one another, to compensate for inaccuracies in the positioning mechanisms of the floppy drives. The Amiga gets it's 880K per floppy by read/writing an entire track at a time. So there's no need for any spacing between tracks. So an Amiga can fit 11 sectors per track, versus the 9 per track on a PC or an ST. The Amiga also uses it's Blitter to decode disk data, versus a disk controller chip. So it can easily read other MFM formats, like the PC or ST format, and can even be programmed to decode stranger formats, like the 8-bit Commodore GCR format. There are commercial programs for the Amiga that let it read both of these, and Apple II as well (which is a very low density format similar in other respects to the Mac format). There's some work being done on getting the Amiga to read Mac format; it can certainly read parts of the Mac disk, but there's some debate as to whether it will be able to read the whole thing or not. > Does anyone in either plane of existance have any ideas on a possible > compromise format? You're probably best sticking with the native ST format, believe it or not. Since that's, at the low levels at least, exactly the same as the PC format, others will come to you, rather than you coming to them. There's no way an ST will read a Mac disk without duplicating the Mac hardware and attaching it to the Mac. I'm not sure how flexible the Mac disk controller is, but I'd imagine that it won't be too long before there's some way for a Mac to read PC, and thus ST, disks. In the same time frame, a way to read and write Mac disks may be viable on the Amiga, so if there's not other way by then, it would be possible to go through an Amiga. > Christopher D. Johnson -- Dave Haynie Commodore-Amiga Usenet: {ihnp4|caip|rutgers}!cbmvax!daveh "The A2000 Guy" PLINK : D-DAVE H BIX : hazy "Catch a wave and you're sittin' on top of the world" -Beach Boys
olson@endor.harvard.edu (Eric Olson) (07/30/87)
I remember hearing something once about Apple changing the IWM (Integrated Wozniak Machine; their disk controller) so that it can read (and maybe write) IBM (Western Digital style controllers) format disks. I know that the IWM was changed from the Mac to the Mac+; I don't know if they actually implemented IBM mode read or write. I definitely have NOT seen any utilities for reading or writing IBM format on a Mac floppy drive. -Eric Eric K. Olson olson@endor.harvard.edu harvard!endor!olson
Sheldon_Hijacker_Chang@cup.portal.com (08/06/87)
I know as of anyone would know the quickest solution is to send it to
your MAC using a modem. Or there's a program out, can't remember the name
I think it reads MAC format disks and transfers them over to ST disks. So
all you need is to format a MAC disk with DC format. What I just said I
heard it from somebody on a BBS, and I can't quite remeber it well.
SHELDON CHANG
sun!cup.portal.com!sheldon.hijacker.chang