From Newsgroup: comp.sys.apple2

I've been told that it is 'impossible' to read Apple-formatted 3.5" disks on
a PC because of the difference in formats. However, since there are tools
such as TransMac, MacDrive 98 and MacOpen 2000 that can read Mac 3.5" HD floppies on PCs, the argument that it is 'impossible' seems a little less persuasive.

If there really is a limitation that prevents reading Apple-formatted 3.5"
DSDD disks on a PC's 3.5" drive, I would guess that it is related to the variable spin rates of the Apple's 3.5" drive. Can anyone point me to a reference on the variable speed drives?

- Mike


--- Synchronet 3.18b-Win32 NewsLink 1.113

From Newsgroup: comp.sys.apple2

In article <yLtQa.13001$D%1.10374@nwrddc01.gnilink.net>,
Michael Pender <mpender@hotmail.com> wrote:

I've been told that it is 'impossible' to read Apple-formatted 3.5"
disks on a PC because of the difference in formats. However, since
there are tools such as TransMac, MacDrive 98 and MacOpen 2000 that
can read Mac 3.5" HD floppies on PCs, the argument that it is
'impossible' seems a little less persuasive.

If there really is a limitation that prevents reading Apple-formatted
3.5" DSDD disks on a PC's 3.5" drive, I would guess that it is
related to the variable spin rates of the Apple's 3.5" drive. Can
anyone point me to a reference on the variable speed drives?

The incompatibility in disk format which makes it impossible to read
Apple disks in standard PC hardware is at the lowest-level encoding:
the Apple II used GCR whihe the PC uses MFM. Early Macs used GCR
too; later MFM disks were used by Mac but a lot of Macs have floppy
drives capable of reading GCR disks too. PC floppy drives have
never been able to read GCR disks and will never be.

That's why it's impossible to read Apple II disks on a PC although
it can be read on many Mac's: you just cannot write software to read
an Apple II disk on a PC (assuming standard PC hardware is used).

Of course there's a way around this: get hardware for your PC which
is capable of reading GCR disks. In this case you must get a floppy
disk controller which can handle the GCR format -- do a web search on "Catweasel" for a company which manufactures such floppy disk
controllers. They're somewhat expensive though..... ...or build
your own hardware...... :-)

However, short of getting new hardware for your PC, there's no way
to read an Apple II disk on your PC.

--
----------------------------------------------------------------

Paul Schlyter, Grev Turegatan 40, SE-114 38 Stockholm, SWEDEN

e-mail: pausch at stockholm dot bostream dot se

WWW: http://www.stjarnhimlen.se/

http://home.tiscali.se/pausch/

--- Synchronet 3.18b-Win32 NewsLink 1.113

From Newsgroup: comp.sys.apple2

In article <3F12E0F8.3000301@snerts-r-us.org>,
sean <abuse@snerts-r-us.org> wrote:

Paul Schlyter wrote:

PC floppy drives have
never been able to read GCR disks and will never be.

Unless of course you are lucky enough to get your hands on an old
Central Point Copy II option board.

Yes -- as I said further down in that post: with special hardware
you will be able to read an Apple II floppy on a PC.

--
----------------------------------------------------------------

Paul Schlyter, Grev Turegatan 40, SE-114 38 Stockholm, SWEDEN

e-mail: pausch at stockholm dot bostream dot se

WWW: http://www.stjarnhimlen.se/

http://home.tiscali.se/pausch/

--- Synchronet 3.18b-Win32 NewsLink 1.113

From Newsgroup: comp.sys.apple2

Paul Schlyter <pausch@saaf.se> wrote in message news:betttj$1b9n$1@merope.saaf.se...

In article <yLtQa.13001$D%1.10374@nwrddc01.gnilink.net>,
Michael Pender <mpender@hotmail.com> wrote:

The incompatibility in disk format which makes it impossible to read
Apple disks in standard PC hardware is at the lowest-level encoding:
the Apple II used GCR whihe the PC uses MFM. Early Macs used GCR
too; later MFM disks were used by Mac but a lot of Macs have floppy
drives capable of reading GCR disks too. PC floppy drives have
never been able to read GCR disks and will never be.

Is a reference available that outlines the differences between GCR and MFM?
If that is the only difference, then it should be possible to read/write PC-format disks on an Apple II, even if the opposite is not true.

- Mike


--- Synchronet 3.18b-Win32 NewsLink 1.113

From Newsgroup: comp.sys.apple2


"Michael Pender" <mpender@hotmail.com> wrote in message news:XAFQa.1178$OC4.956@nwrddc01.gnilink.net...

Paul Schlyter <pausch@saaf.se> wrote in message news:betttj$1b9n$1@merope.saaf.se...

In article <yLtQa.13001$D%1.10374@nwrddc01.gnilink.net>,
Michael Pender <mpender@hotmail.com> wrote:

The incompatibility in disk format which makes it impossible to read
Apple disks in standard PC hardware is at the lowest-level encoding:
the Apple II used GCR whihe the PC uses MFM. Early Macs used GCR
too; later MFM disks were used by Mac but a lot of Macs have floppy
drives capable of reading GCR disks too. PC floppy drives have
never been able to read GCR disks and will never be.

Is a reference available that outlines the differences between GCR and MFM? If that is the only difference, then it should be possible to read/write PC-format disks on an Apple II, even if the opposite is not true.

An Apple 3.5" (800K) drive is capable of reading/writing PC-format disks (720K) but the Apple controller is not. I use an Applied Engineering PC Transporter card with an Apple 3.5" drive attached to it. It works perfectly with 720K MS-DOS disks as long as they are formatted on a real PC. When using the Apple 3.5" drive for ProDOS the speed is slower than if it was attached to the Apple (SmartPort) controller.

It is my understanding that Apple 5.25" drives cannot read/write MFM at all.

Charlie






--- Synchronet 3.18b-Win32 NewsLink 1.113

From Newsgroup: comp.sys.apple2

In article <XAFQa.1178$OC4.956@nwrddc01.gnilink.net>,
Michael Pender <mpender@hotmail.com> wrote:

Paul Schlyter <pausch@saaf.se> wrote in message news:betttj$1b9n$1@merope.saaf.se...

In article <yLtQa.13001$D%1.10374@nwrddc01.gnilink.net>,
Michael Pender <mpender@hotmail.com> wrote:

The incompatibility in disk format which makes it impossible to read
Apple disks in standard PC hardware is at the lowest-level encoding:
the Apple II used GCR whihe the PC uses MFM. Early Macs used GCR
too; later MFM disks were used by Mac but a lot of Macs have floppy
drives capable of reading GCR disks too. PC floppy drives have
never been able to read GCR disks and will never be.

Is a reference available that outlines the differences between GCR and MFM? If that is the only difference, then it should be possible to read/write PC-format disks on an Apple II, even if the opposite is not true.

I've never seen any reference comparing MFM and GCR.

However, GCR is described in "Beneath Apple ProDos". There also was
a description in "Beneath Apple DOS" which was inaccurate; the
corrected description appears in "Beneath Apple ProDos".

Both GCR and MFM are based on FM, where every other pulse is a clock
pulse (always "1") and every other pulse a data pulse. GCR is just
FM with all the clock pulses removed. MFM is another way to compress
the data, by writing some of the pulses at "half-pulse" positions.


--
----------------------------------------------------------------

Paul Schlyter, Grev Turegatan 40, SE-114 38 Stockholm, SWEDEN

e-mail: pausch at stockholm dot bostream dot se

WWW: http://www.stjarnhimlen.se/

http://home.tiscali.se/pausch/

--- Synchronet 3.18b-Win32 NewsLink 1.113

From Newsgroup: comp.sys.apple2

In article <APMQa.2286$r8.407@nwrddc02.gnilink.net>,
Michael Pender <mpender@hotmail.com> wrote:

Charlie <charlied@NOSPAMbboard.com> wrote in message news:bevseq01g3@enews2.newsguy.com...

It is my understanding that Apple 5.25" drives cannot read/write MFM
at all.

I don't see why not - the Apple 5.25" drive is controlled entirely by software.

Not quite...

The Apple II disk controller card has two ROMs of 256 bytes each.
The first contains the boot code. But the second isn't available
at all from the 6502 address bus -- it's a "state machine ROM"
used by the hardware logic on the disk controller card.

When the Apple II switched from 13-sector to 16-sector disks, both
ROM's had the be upgraded.

With a change to the software it should be able to read MFM disks
without difficulty.

...you'd have to change the "state machine ROM" as well. It needed
an upgrade when Apple went from 13-sector to 16-sector disks.

Of course, saying that it is *possible* is very different than
saying its worth the time to do.

It's at least impossible without updating the "state machine ROM".
And updating that just to read MFM disks on the Apple II isn't
worth doing....

--
----------------------------------------------------------------

Paul Schlyter, Grev Turegatan 40, SE-114 38 Stockholm, SWEDEN

e-mail: pausch at stockholm dot bostream dot se

WWW: http://www.stjarnhimlen.se/

http://home.tiscali.se/pausch/

--- Synchronet 3.18b-Win32 NewsLink 1.113

From Newsgroup: comp.sys.apple2

sean wrote:

Paul Schlyter wrote:

PC floppy drives have
never been able to read GCR disks and will never be.

Unless of course you are lucky enough to get your hands on an old
Central Point Copy II option board.

Hmm. I have one of these. However, I'm not aware that the support
software lets you read files from, e.g. a IIgs 3.5" disk. Wasn't it
just intended for full-disk copying?



--- Synchronet 3.18b-Win32 NewsLink 1.113

From Newsgroup: comp.sys.apple2

In article <FTaRa.1576$KZ.854103@news1.news.adelphia.net>,
Steven N. Hirsch <shirsch@adelphia.net> wrote:

sean wrote:

Paul Schlyter wrote:

PC floppy drives have
never been able to read GCR disks and will never be.

Unless of course you are lucky enough to get your hands on an old
Central Point Copy II option board.

Hmm. I have one of these. However, I'm not aware that the support
software lets you read files from, e.g. a IIgs 3.5" disk. Wasn't it
just intended for full-disk copying?

I think he meant the capability of the hardware and not necessarily
the accompanying software. You can always write your own software,
but it's much harder to build your own hardware.... :-)

--
----------------------------------------------------------------

Paul Schlyter, Grev Turegatan 40, SE-114 38 Stockholm, SWEDEN

e-mail: pausch at stockholm dot bostream dot se

WWW: http://www.stjarnhimlen.se/

http://home.tiscali.se/pausch/

--- Synchronet 3.18b-Win32 NewsLink 1.113

From Newsgroup: comp.sys.apple2

Willi Kusche schrieb:

Speaking of new hardware, or rather, different old hardware, you
could pick up an Amiga 1000 and an Amiga 1020 5.25 inch drive and copy directly from 5.25 Apple disks in the A1020 to MS/DOS 3.5 inch
standard density disks in the internal 3.5 inch drive of the A1000.

Speaking of new hardware, you can connect your Disk II drive to your
PC's printer port and write some really efficient assembler code. A
state machine like that designed by Woz in the late '70s may help. Or a complete disk II controller card. Replace the '259er with a parallel
latch, and only two bytes will be needed.


Patrick
--- Synchronet 3.18b-Win32 NewsLink 1.113

From Newsgroup: comp.sys.apple2

In <bf43io$j8r$1@merope.saaf.se> Paul Schlyter wrote:

In article <FTaRa.1576$KZ.854103@news1.news.adelphia.net>,
Steven N. Hirsch <shirsch@adelphia.net> wrote:

sean wrote:

Paul Schlyter wrote:

PC floppy drives have
never been able to read GCR disks and will never be.

Unless of course you are lucky enough to get your hands on an old
Central Point Copy II option board.

Hmm. I have one of these. However, I'm not aware that the support
software lets you read files from, e.g. a IIgs 3.5" disk. Wasn't it
just intended for full-disk copying?

I think he meant the capability of the hardware and not necessarily
the accompanying software. You can always write your own software,
but it's much harder to build your own hardware.... :-)

It could copy Apple GCR disks, but it also came with software for
reading files from Mac 400KB and 800KB disks, so you should be able to
use it for transferring files to a IIgs as long as you use the HFS
format.

More info at http://retro.icequake.net/dob/

--
Roger Johnstone, Invercargill, New Zealand

Apple II - FutureCop:LAPD - iMac Game Wizard http://homepages.ihug.co.nz/~rojaws/ ________________________________________________________________________
"Never underestimate the bandwidth of a station wagon full of tapes
hurtling down the highway."

Andrew S. Tanenbaum, Computer_Networks, Second Edition, p. 57
--- Synchronet 3.18b-Win32 NewsLink 1.113

From Newsgroup: comp.sys.apple2

Paul Schlyter wrote:

In article <FTaRa.1576$KZ.854103@news1.news.adelphia.net>,
Steven N. Hirsch <shirsch@adelphia.net> wrote:

sean wrote:

Paul Schlyter wrote:

PC floppy drives have
never been able to read GCR disks and will never be.

Unless of course you are lucky enough to get your hands on an old
Central Point Copy II option board.

Hmm. I have one of these. However, I'm not aware that the support
software lets you read files from, e.g. a IIgs 3.5" disk. Wasn't it
just intended for full-disk copying?

I think he meant the capability of the hardware and not necessarily
the accompanying software. You can always write your own software,
but it's much harder to build your own hardware.... :-)

Considering that it would be necessary to write RWTS and a
pretty complete file system (or two) in x86 code, I think this
may be yet another case where the hardware is the easyware
and the software is the hardware. ;-)

-michael

Check out amazing quality 8-bit Apple sound on my
Home page: http://members.aol.com/MJMahon/
--- Synchronet 3.18b-Win32 NewsLink 1.113

From Newsgroup: comp.sys.apple2

In article <20030723040500.21622.00000401@mb-m07.aol.com>,
Michael J. Mahon <mjmahon@aol.com> wrote:

Paul Schlyter wrote:

In article <FTaRa.1576$KZ.854103@news1.news.adelphia.net>,
Steven N. Hirsch <shirsch@adelphia.net> wrote:

sean wrote:

Paul Schlyter wrote:

PC floppy drives have
never been able to read GCR disks and will never be.

Unless of course you are lucky enough to get your hands on an old
Central Point Copy II option board.

Hmm. I have one of these. However, I'm not aware that the support
software lets you read files from, e.g. a IIgs 3.5" disk. Wasn't it
just intended for full-disk copying?

I think he meant the capability of the hardware and not necessarily
the accompanying software. You can always write your own software,
but it's much harder to build your own hardware.... :-)

Considering that it would be necessary to write RWTS

Only if the hardware is as stupid as the standard Apple II disk
"controller" (which was only a rudimentary disk controller really;
the Apple II RWTS was the actual "disk controller"). With any real
disk controller chip, you just set some parameters in the disk
controller, then give it a memory address and tell it to read one or
several consecutive sectors into a buffer starting at that address.

and a pretty complete file system (or two) in x86 code,

Anyone wanting to attempt that are free to borrow as much C code
as they want from my FID.C (available at http://home.tiscali.se/pausch/apple2/) to access an Apple DOS file system.

I think this may be yet another case where the hardware is the
easyware and the software is the hardware. ;-)

Only if the software really would require a complex RWTS equivalent
and the hardware contained only standard components which you could
buy fairly easily. But when I said "build your own hardware" I was
more thinking of constructing and mask programming your own LSI
chips....... it's not impossible, but it's definitely not for the
faint hearted to do such a thing.

But before speculating more, we need to know more about the hardware:
does it contain a real disk controller in hardware, which is at least reasonably "intelligent"? Or does it contain only a rudimentary disk controller in hardware, like the Apple II did?

--
----------------------------------------------------------------

Paul Schlyter, Grev Turegatan 40, SE-114 38 Stockholm, SWEDEN

e-mail: pausch at stockholm dot bostream dot se

WWW: http://www.stjarnhimlen.se/

http://home.tiscali.se/pausch/

--- Synchronet 3.18b-Win32 NewsLink 1.113

From Newsgroup: comp.sys.apple2

"Paul Schlyter" <pausch@saaf.se> wrote in message news:bfm3n4$gvv$1@merope.saaf.se...

Anyone wanting to attempt that are free to borrow as much C code
as they want from my FID.C (available at

http://home.tiscali.se/pausch/apple2/)

to access an Apple DOS file system.

It is a kind offer, but since the FID code works with DSK images instead of dealing with physical disks I don't think the code would really help. What
we really need is source code for a track editor for the IBM PC and the
Apple. The code of a program like Locksmith that deals with nibble-based protection schemes would take us a long way.

- Mike



--- Synchronet 3.18b-Win32 NewsLink 1.113

From Newsgroup: comp.sys.apple2

In article <BvATa.56060$EZ2.15949@nwrddc01.gnilink.net>,
news.verizon.net <mpender@hotmail.com> wrote:

"Paul Schlyter" <pausch@saaf.se> wrote in message news:bfm3n4$gvv$1@merope.saaf.se...

Anyone wanting to attempt that are free to borrow as much C code
as they want from my FID.C (available at
http://home.tiscali.se/pausch/apple2/)
to access an Apple DOS file system.

It is a kind offer, but since the FID code works with DSK images instead of dealing with physical disks I don't think the code would really help.

You have obviously not looked at that code.....

It has a (logical) "Read Sector" function, which of course only
indexes into the DSK image and copies a 256-byte block from there.
But if you replace that with a function which reads a real sector off
a real disk, then the file system parts ought to work fine if it's an
Apple DOS 3.3 disk. Yep, I had that possibility in mind when I wrote
that code .... no I don't have any concrete plans in that direction,
but OTOH you'll never know what use your code may find.

What we really need is source code for a track editor for the IBM PC and
the Apple. The code of a program like Locksmith that deals with nibble- based protection schemes would take us a long way.

Well, if you want to dabble with the disk at the nibble level, I guess
you don't need to worry too much about the file system..... :-)

--
----------------------------------------------------------------

Paul Schlyter, Grev Turegatan 40, SE-114 38 Stockholm, SWEDEN

e-mail: pausch at stockholm dot bostream dot se

WWW: http://www.stjarnhimlen.se/

http://home.tiscali.se/pausch/

--- Synchronet 3.18b-Win32 NewsLink 1.113

From Newsgroup: comp.sys.apple2

From my Copy IIPC Deluxe Option Board Manual:

Commands:
MDIR:- mac DIRectory- all files in current folder
MTREE:- show all folders on disk
MTYPE :- lists file to screen
MCOPY:- copies files
MFORMAT :- formats a MAC 400K or 800K (sorry doesn't do 1.44)
MCD :- change directory
MDC:-Copies a MAC Diskette
MDEL :- Deletes files
MMD :- make new folder
MRD :-removes a folder

Note all commands need a full DOS pathname

400K disks wil be MFS format MFORMAT A: /4

800K disks will be HFS format MFORMAT A:

from the Manual: "Making backups of NON-IBM Disks"

Btw :-TC stands for "transition copier"

"TC can be used to create backups of nearly all IBM PC compatable disks. It can also duplicate most other formats. Because TC simply copies magnetic transitions from one disk to another, it is not too concerned with how those transitions are created or ordered. Diskette formats can be grouped into three basic types:

MFM example: IBM PC, Kaypro, Amiga
FM example: Atari
GCR example :Apple (Ed, not refering to MAC)

The Deluxe Option Board and TC can copy all of the above formats.(Standard Apple and Atari formats are copied readily. The TC software MAY NOT (Ed. my emph) be able to copy all protected Apple and Atari disks, however. It also can't copy the backside of "flippy" diskettes.( Ed. what are those?) It should be noted that not all IBM drives are capable of reliably reading and writing GCR formats (Apple disks). The only way to know is to try."

I actually formatted MAC disks and read and wrote files both ways. I did however get a lot of error disks, (formatted and the said disk unreadable on last track). This however was all my fault as I was trying to use 1.44 disks to format 800K. D'oh. Got some of my Apple II disks and everthing went smooth. Did not try to copy a Apple II disk however. Had one TEAC drive (recommended in manual. Worked but later the drive died (not related). Stuck a Chinon (standard cheap drive), worked fine with 800k disks.

Also:

Drives: Read 1.44M drive write to 360k 3.5 or 720k 3.5 or 1.44 M drives
Cannot read 720k 3.5 or 360k 3.5 drives and write to1.44M drive
Cannot write to 1.44M Diskettes
Read from 720K 3.5 drive (special instructions to copy all 80 tracks)
Copying from 5.25 to 3.5 ends up as a 360k 3.5 diskette
Read 1.2M 5.25 drive write to 360k or 720k drives
Read from 1.2M write to 1.2M drive
Cannot read from 360k or 720k and write to1.2M drive
Cannot read or write to 1.2M diskettes

the above is condensed and confusing! Try reading the original!!

Wayne Lafreniere


"news.verizon.net" wrote:

"Paul Schlyter" <pausch@saaf.se> wrote in message news:bfmno3$1a2m$1@merope.saaf.se...

In article <BvATa.56060$EZ2.15949@nwrddc01.gnilink.net>,
news.verizon.net <mpender@hotmail.com> wrote:

It is a kind offer, but since the FID code works with DSK images instead

of

dealing with physical disks I don't think the code would really help.

You have obviously not looked at that code.....

It has a (logical) "Read Sector" function, which of course only
indexes into the DSK image and copies a 256-byte block from there.
But if you replace that with a function which reads a real sector off
a real disk, then the file system parts ought to work fine if it's an
Apple DOS 3.3 disk. Yep, I had that possibility in mind when I wrote
that code .... no I don't have any concrete plans in that direction,
but OTOH you'll never know what use your code may find.

The "function which reads a real sector" is the part that's hard to write. Once we can read the physical media, the process of making a DSK file is a piece of cake.

- Mike

--- Synchronet 3.18b-Win32 NewsLink 1.113

From Newsgroup: comp.sys.apple2

Paul Schlyter replied:

In article <20030723040500.21622.00000401@mb-m07.aol.com>,
Michael J. Mahon <mjmahon@aol.com> wrote:

Paul Schlyter wrote:

In article <FTaRa.1576$KZ.854103@news1.news.adelphia.net>,
Steven N. Hirsch <shirsch@adelphia.net> wrote:

sean wrote:

Paul Schlyter wrote:

PC floppy drives have
never been able to read GCR disks and will never be.

Unless of course you are lucky enough to get your hands on an old
Central Point Copy II option board.

Hmm. I have one of these. However, I'm not aware that the support
software lets you read files from, e.g. a IIgs 3.5" disk. Wasn't it
just intended for full-disk copying?

I think he meant the capability of the hardware and not necessarily
the accompanying software. You can always write your own software,
but it's much harder to build your own hardware.... :-)

Considering that it would be necessary to write RWTS

Only if the hardware is as stupid as the standard Apple II disk
"controller" (which was only a rudimentary disk controller really;
the Apple II RWTS was the actual "disk controller"). With any real
disk controller chip, you just set some parameters in the disk
controller, then give it a memory address and tell it to read one or
several consecutive sectors into a buffer starting at that address.

The Copy II Plus Option Board is _not_ a disk controller chip.
It is an extremely low-level device--which is why it can
capture virtually any bit stream from a disk.

and a pretty complete file system (or two) in x86 code,

Anyone wanting to attempt that are free to borrow as much C code
as they want from my FID.C (available at >http://home.tiscali.se/pausch/apple2/)
to access an Apple DOS file system.

It is good to know that there is source available which could
form the starting point for several file systems.

I think this may be yet another case where the hardware is the
easyware and the software is the hardware. ;-)

Only if the software really would require a complex RWTS equivalent
and the hardware contained only standard components which you could
buy fairly easily. But when I said "build your own hardware" I was
more thinking of constructing and mask programming your own LSI
chips....... it's not impossible, but it's definitely not for the
faint hearted to do such a thing.

But before speculating more, we need to know more about the hardware:
does it contain a real disk controller in hardware, which is at least >reasonably "intelligent"? Or does it contain only a rudimentary disk >controller in hardware, like the Apple II did?

The Copy II Plus Option Board is a totally rudimentary bit stream
capture device. To my knowledge there are _no_ disk controller
chips that have ever supported Apple GCR. (Even the SWIM chip
is a nibble capture device, comparable to the Disk ][ controller.)

It is also unfortunate that the bit-level I/O available on even the
fastest PCs, like the parallel port, is limited to about 500KHz
sampling rates (due to the legacy ISA timing), and so is not
fast enough to accurately sample head data without interposing
a serial-to-parallel converter running at 2MHz or so. And then
there are the ubiqitous interrupts of most PC environments...

I've been tempted to build such an adapter to a Disk ][, but so
far there are simpler options for moving data between my //e
and my PC (some involving a Mac ;-).

-michael

Check out amazing quality 8-bit Apple sound on my
Home page: http://members.aol.com/MJMahon/
--- Synchronet 3.18b-Win32 NewsLink 1.113