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Write 800k Floppies?
- Thread starter ScMla
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Anonymous Freak
Well-known member
Sorry, not possible.
Mac 800k floppies use a physical method of reading and writing that is completely incompatible with PC floppy drives. All USB floppy drives are really just standard PC floppy drives, so they won't work with 800k Mac disks.
You'll need a "beige"-era Mac with a built-in floppy drive to read and write 800k Mac floppy disks.
(When Apple moves to 1.4 MB disks, they went with the PC standard method of reading and writing; but their floppy *DRIVES* still had to be compatible with their previous non-standard 800k and 400k disks; so while Apple's 1.4 MB drives can read and write any 400k, 800k or 1.4 MB Mac disk, as well as any 720k or 1.4 MB PC disk, the PC world didn't reciprocate.)
Mac 800k floppies use a physical method of reading and writing that is completely incompatible with PC floppy drives. All USB floppy drives are really just standard PC floppy drives, so they won't work with 800k Mac disks.
You'll need a "beige"-era Mac with a built-in floppy drive to read and write 800k Mac floppy disks.
(When Apple moves to 1.4 MB disks, they went with the PC standard method of reading and writing; but their floppy *DRIVES* still had to be compatible with their previous non-standard 800k and 400k disks; so while Apple's 1.4 MB drives can read and write any 400k, 800k or 1.4 MB Mac disk, as well as any 720k or 1.4 MB PC disk, the PC world didn't reciprocate.)
benjgvps
Well-known member
So, hold one here! If I say, hook the floppy drive up to a USB to IDE adapter, and the eject mechanism was somehow compatible, I could probably write 800k floppies? I think I might have a spare one from a busted 150... All I need now is a USB to IDE cable. Off to dealextreme.com!
LCGuy
LC Doctor/Hot Rodder
The hard drive is a standard 2.5" IDE device, exactly the same as those used in 90% of all laptops out there.
However, the floppy drive is a completely different matter, its the same interface as whats used on classic desktop Macs, just with a smaller, more PowerBook-friendly cable and connectors. The only drive you can plug in there is another floppy drive from another PowerBook. (PB150 needs manual inject, btw, such as those used in PowerPC 'Books) The interface has absolutely nothing in common with IDE, or even the PC floppy drive interface. As JRL said, its an Apple-only standard, never used by anyone apart from Apple.
However, the floppy drive is a completely different matter, its the same interface as whats used on classic desktop Macs, just with a smaller, more PowerBook-friendly cable and connectors. The only drive you can plug in there is another floppy drive from another PowerBook. (PB150 needs manual inject, btw, such as those used in PowerPC 'Books) The interface has absolutely nothing in common with IDE, or even the PC floppy drive interface. As JRL said, its an Apple-only standard, never used by anyone apart from Apple.
tomlee59
Well-known member
You seem to be assuming that the use of an IDE hard drive somehow implies that the floppy interface is also IDE. I don't know why you would make that association -- it would be unique among computers if it were so. A scsi-equipped mac does not have a scsi floppy drive; PCs with IDE hard drives have proprietary floppy interfaces that, although sharing a common heritage with IDE, are not themselves IDE.
Floppy and hard drives have very different characteristics, and their interfaces evolved independently as a result.
And no, the 150's floppy interface is not just an IDE with "pins switched around." I really meant what I wrote earlier: The floppy interface in a Mac is nowhere near IDE in design.
II2II
Well-known member
To my knowledge, the actual limitation isn't the floppy drive itself. That is to say that a PC floppy drive could read or write 800 kB floppies.
BUT
Old Mac and PC floppy drives are nothing like USB floppy drives. The old devices were low level devices that needed a special controller to do a lot of the work for it (e.g. telling the motor that moves the drive head when to start and when to stop).
This means that the floppy drive controller is not the only piece of hardware that you have to consider. The other piece of hardware that you have to consider is the floppy drive controller. So even if a PC and Mac floppy drive were electrically compatible (which they are not), you still could not hook-up a Mac floppy drive to a PC floppy drive controller and expect it to read or write Mac floppy diskettes.
BUT
Old Mac and PC floppy drives are nothing like USB floppy drives. The old devices were low level devices that needed a special controller to do a lot of the work for it (e.g. telling the motor that moves the drive head when to start and when to stop).
This means that the floppy drive controller is not the only piece of hardware that you have to consider. The other piece of hardware that you have to consider is the floppy drive controller. So even if a PC and Mac floppy drive were electrically compatible (which they are not), you still could not hook-up a Mac floppy drive to a PC floppy drive controller and expect it to read or write Mac floppy diskettes.
Anonymous Freak
Well-known member
Here you go:
Apple's floppy drives are unique in that they have almost no circuitry on the drive themselves. The drive is just a dumb set of motors and heads. The floppy drive controller chip resides on a board in the computer. This is true from the Apple II all the way up to the beige G3 and PowerBook G3. On the Apple II, it was an add-in controller card, on all Macs (again, up to the beige G3 and the last PowerBook G3 with a floppy drive,) it's on the motherboard. There is only one cable running in to an Apple floppy drive. This cable contains all of the 'raw' data pins, as well as the power to run the motors.
On a PC, much of the electronics are on the drive itself. The controller on the motherboard (or, on very early PCs, an add-in card,) is much simpler than the chip on a Mac. This is because the drive itself has some 'smarts' to it. This also means that the floppy drive needs its own separate power. The data cable carries not the raw 'straight-from-the-heads' data, but is similar in concept (if not implementation) as IDE and SCSI in that the data arrives packaged. (Note that even though my explanation is long winded, it's still technically simplified, so some things are technically inaccurate in the name of ease of understanding.)
The big deal here is that, for example, a PC that can only talk to a 720 KB floppy drive, is incapable of using a 1440 KB floppy drive. This is because the controller won't speak the same language as the drive. On a Mac, you can slap a 1.4 MB "SuperDrive" into a computer that only understands 800K drives, because the raw electronics in the drive are the same, only the read head's ability to deal with the newer disks is different. It's just that in an 800K-only computer, the drive will act exactly as an 800K drive, since the controller chip doesn't know about 1.4 MB disks.
The deal is that when Apple introduced the 1.4 MB controller chip, they not only added the ability to read and write High Density disks, but they changed the raw method in which the disks are read to and written from to be the same physical style as PC disks. Then all it took was software to be able to read and write PC disks. Unfortunately, because of the difference in the physical style of writing lower-density disks, PCs could not just have software to let them read Mac lower-density disks.
But, the ability to read and write older 400K and 800K Mac disks remained. My PowerBook 100 running System 6 has no problems reading my MacWrite 1.0 disk from an original Macintosh 128k.
Because the two mechanisms are so different (Mac vs. PC) anything[/i that assumes a PC-style floppy drive (wether an actual PC, or a USB floppy drive case,) will not work with a Macintosh floppy drive, and therefore, no Macintosh 400K or 800K disks. (In spite of the similar nature of notebook floppy drives on PCs vs. Macs, PC notebook drives still use the same PC floppy interface, only with a smaller physical plug; and Mac drives still use the same Mac floppy interface, only with a smaller physical plug.)
Finally, the PC floppy interface predates IDE (Properly called "ATA") by quite a few years, and is a completely separate interface. You can *NOT* plug a PC floppy drive (of any kind) into a PC ATA controller (of any kind.) (Just as you cannot plug a Mac floppy drive into a SCSI port.) It just so happens that many PC notebooks (and even a few Mac notebooks,) used the same physical 'expansion bay' for both floppy drives and hard drives or ATA optical drives. The electrical signal is 100% separate, though. They go through the same physical plug, but the physical plug carries both kinds of signals on different pins. The device plugged in is just wired to the proper pins. (This idea exists in the new notebook computer expansion card "ExpressCard", used on the MacBook Pros as well as many PC notebooks. The slot contains both pins for PCI Express as well as USB. The card manufacturer decides which set of pins they want to use. For example, I have a FireWire 800 card that uses the PCI Express pins, and a flash memory card reader that uses the USB pins. So in System Profiler, one appears under "PCI Express", one appears under "USB".)
Apple's floppy drives are unique in that they have almost no circuitry on the drive themselves. The drive is just a dumb set of motors and heads. The floppy drive controller chip resides on a board in the computer. This is true from the Apple II all the way up to the beige G3 and PowerBook G3. On the Apple II, it was an add-in controller card, on all Macs (again, up to the beige G3 and the last PowerBook G3 with a floppy drive,) it's on the motherboard. There is only one cable running in to an Apple floppy drive. This cable contains all of the 'raw' data pins, as well as the power to run the motors.
On a PC, much of the electronics are on the drive itself. The controller on the motherboard (or, on very early PCs, an add-in card,) is much simpler than the chip on a Mac. This is because the drive itself has some 'smarts' to it. This also means that the floppy drive needs its own separate power. The data cable carries not the raw 'straight-from-the-heads' data, but is similar in concept (if not implementation) as IDE and SCSI in that the data arrives packaged. (Note that even though my explanation is long winded, it's still technically simplified, so some things are technically inaccurate in the name of ease of understanding.)
The big deal here is that, for example, a PC that can only talk to a 720 KB floppy drive, is incapable of using a 1440 KB floppy drive. This is because the controller won't speak the same language as the drive. On a Mac, you can slap a 1.4 MB "SuperDrive" into a computer that only understands 800K drives, because the raw electronics in the drive are the same, only the read head's ability to deal with the newer disks is different. It's just that in an 800K-only computer, the drive will act exactly as an 800K drive, since the controller chip doesn't know about 1.4 MB disks.
The deal is that when Apple introduced the 1.4 MB controller chip, they not only added the ability to read and write High Density disks, but they changed the raw method in which the disks are read to and written from to be the same physical style as PC disks. Then all it took was software to be able to read and write PC disks. Unfortunately, because of the difference in the physical style of writing lower-density disks, PCs could not just have software to let them read Mac lower-density disks.
But, the ability to read and write older 400K and 800K Mac disks remained. My PowerBook 100 running System 6 has no problems reading my MacWrite 1.0 disk from an original Macintosh 128k.
Because the two mechanisms are so different (Mac vs. PC) anything[/i that assumes a PC-style floppy drive (wether an actual PC, or a USB floppy drive case,) will not work with a Macintosh floppy drive, and therefore, no Macintosh 400K or 800K disks. (In spite of the similar nature of notebook floppy drives on PCs vs. Macs, PC notebook drives still use the same PC floppy interface, only with a smaller physical plug; and Mac drives still use the same Mac floppy interface, only with a smaller physical plug.)
Finally, the PC floppy interface predates IDE (Properly called "ATA") by quite a few years, and is a completely separate interface. You can *NOT* plug a PC floppy drive (of any kind) into a PC ATA controller (of any kind.) (Just as you cannot plug a Mac floppy drive into a SCSI port.) It just so happens that many PC notebooks (and even a few Mac notebooks,) used the same physical 'expansion bay' for both floppy drives and hard drives or ATA optical drives. The electrical signal is 100% separate, though. They go through the same physical plug, but the physical plug carries both kinds of signals on different pins. The device plugged in is just wired to the proper pins. (This idea exists in the new notebook computer expansion card "ExpressCard", used on the MacBook Pros as well as many PC notebooks. The slot contains both pins for PCI Express as well as USB. The card manufacturer decides which set of pins they want to use. For example, I have a FireWire 800 card that uses the PCI Express pins, and a flash memory card reader that uses the USB pins. So in System Profiler, one appears under "PCI Express", one appears under "USB".)
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