Tabakal@UB.CC.UMICH.EDU (02/01/91)
Okay, I'm going to try to clear up some misinformation about the
PC Transporter that has been published lately. Funny, because
some of the info. has come from people who claim to know from
working for AE. There is no SWIM chip on the PCT. SWIM is a chip
designed and owned by Apple. It was created for some of the
Macintosh models years after the PCT was designed by Little Blue
company.
On the other hand, the PCT does have circuitry that allows the
Apple 3.5 disk to read (and *format*) MFM as well as GCR when the
drive is attached to the card instead of the Smartport. When the
drive is attached to the Smartport, the card can do a
pseudo-MSDOS on GCR formatted media.
The reason that the disks are not always readable does not have
to do with the encoding but simply that the Apple drives do not
make use of the Index hole whereas MS-DOS 3.5 disks do. So, if
you luck out, the rotation speed of your drive will align the
data on a PCT-formatted disk to MS-DOS specs, and your
PC-compatible drive will be able to read the disk. Most of the
time, it won't however. Note: this doesn't make a difference to
other PCT units since they ignore index hole timing. If you
format on a normal MS-DOS machine, the disks will be able to be
read on those machines since the index hole spacing/timing lines
up, and the PCT ignores it.
So, to repeat, there is no SWIM chip on the PCT. SWIM is an Apple
standard with a definite meaning. It is a replacement for the IWM
chip on the GS motherboard and it expressly allows for working
with 1.44 Meg disks, something the PCT does not.
-----------------------------------------------------------------------------
Todd A. Bakal Coming soon:
U of M Apple User's Group a new, improved
Ann Arbor, Michigan tested, UN*X archive
Internet: Tabakal@ub.cc.umich.edu FTP: ummts.cc.umich.edu
BITnet: UserTBKL@UMICHUB 35.1.1.43
UUCP: ...!uunet!ub.cc.umich.edu!tabakal CD PC5:daveh@ccwf.cc.utexas.edu (David H. Huang) (02/02/91)
In article <7467609@ub.cc.umich.edu> Tabakal@UB.CC.UMICH.EDU writes: >working for AE. There is no SWIM chip on the PCT. SWIM is a chip That's sounds reasonable. >On the other hand, the PCT does have circuitry that allows the >Apple 3.5 disk to read (and *format*) MFM as well as GCR when the >drive is attached to the card instead of the Smartport. When the That does too. >The reason that the disks are not always readable does not have >to do with the encoding but simply that the Apple drives do not >make use of the Index hole whereas MS-DOS 3.5 disks do. So, if I don't know about that one though. There is no index hole on a 3.5" disk. Unless you mean that hole in the metal disk in the center. Isn't that just a good way for the disk drive to lock onto the disk and turn it? >----------------------------------------------------------------------------- > > Todd A. Bakal Coming soon: > U of M Apple User's Group a new, improved > Ann Arbor, Michigan tested, UN*X archive > > Internet: Tabakal@ub.cc.umich.edu FTP: ummts.cc.umich.edu > BITnet: UserTBKL@UMICHUB 35.1.1.43 > UUCP: ...!uunet!ub.cc.umich.edu!tabakal CD PC5: -- David Huang | Internet: daveh@ccwf.cc.utexas.edu | "My ganglion is stuck in UUCP: ...!ut-emx!ccwf.cc.utexas.edu!daveh | a piece of chewing gum!" America Online: DrWho29 |
jeffh@HyperMail.apple.com (Jeff Holcomb) (02/02/91)
In article <7467609@ub.cc.umich.edu> Tabakal@UB.CC.UMICH.EDU writes: > Okay, I'm going to try to clear up some misinformation about the > PC Transporter that has been published lately. Funny, because > some of the info. has come from people who claim to know from > working for AE. There is no SWIM chip on the PCT. SWIM is a chip > designed and owned by Apple. It was created for some of the > Macintosh models years after the PCT was designed by Little Blue > company. Todd, who do you think created the SWIM chip? The letters SWIM stand for Sanders-Wozniak Integrated Machine. Wendell Sanders took the IWM and made the modifications to add the extra features. After that, he left Apple and started his own company, The Engineering Department, who designed the PCT. The chip on the PCT in question is the only one on the board that has an Apple Copyright. Apparently, Apple licensed the technology to TED who in turn used it on the PCT. There is a difference between the SWIM on the Mac and the PCT, the PCT's can't r/w 1.44 Meg disks (I think). It is possible that the technology is in the PCT's drive chip, but I don't remember anyone at AE ever investigating whether it would work with 1.44 Meg disks or not. :-) ___________________________________________________________________________ Jeff Holcomb Internet: jeffh@HyperMail.apple.com AppleLink: jeffh@HyperMail.apple.com@INTERNET# GEnie: A2.JEFFH Contracting for Apple ATG Voice: (408) 974-0841 My opinions are not necessarily those of Apple. :-P ___________________________________________________________________________