Apple SuperDrive
| Apple SuperDrive | |
|---|---|
 |
|
| External Apple SuperDrive with an Apple II 3.5 Disk Controller Card | |
| Manufacturer | Apple Computer, Inc. |
| Type | 3.5-inch high-density floppy disk drive |
| Interface | DB-19 disk drive port |
| Compatible | Macintosh models with the SWIM controller (1.4 MB); other Macintosh disk ports, Apple IIGS and Apple IIc Plus (400K and 800K); Apple IIe and Apple IIGS with the Apple II 3.5 Disk Controller Card (1.4 MB) |
| Predecessor | Apple 3.5 Drive |
| Model | G7287 (external drive) |
| Media | 3.5-inch 400K, 800K and 1.4 MB disks; 720K and 1.4 MB MS-DOS disks on a Macintosh |
The Apple FDHD drive, also called the SuperDrive, is Apple's high-density 3.5-inch floppy drive. It was fitted internally to the Macintosh SE FDHD, SE/30, Portable, IIx, IIcx, IIci and IIfx, and uses Apple's SWIM controller.[1][2] The external Apple SuperDrive (G7287) connects to the disk drive port of a Macintosh or an Apple II. It reads and writes 400K, 800K and 1.4 MB disks and, on a Macintosh with suitable software, MS-DOS disks.[3] Apple gives the high-density capacity as 1.4 MB.[4]
Formats
| Disk type | Capacity | File system | Encoding |
|---|---|---|---|
| 3.5-inch single sided | 400K | MFS | Apple GCR |
| 3.5-inch double sided | 800K | HFS | Apple GCR |
| 3.5-inch double sided | 720K | MS-DOS | MFM |
| 3.5-inch high density | 1.4 MB | HFS | Apple GCR |
| 3.5-inch high density | 1.4 MB | MS-DOS | MFM |
The Macintosh 1.4 MB format uses Apple GCR. MFM is used only for the MS-DOS formats.[4] Under GCR with NRZI encoding a transition occurs for a one and none for a zero, and the driver formats the data so that more than two adjacent zeros never occur. Under MFM a transition occurs for a one, none for an isolated zero, and one for two adjacent zeros.[4] Four bytes of GCR-encoded data carry three bytes of data.[2]
SWIM controller
The SWIM (Super Woz Integrated Machine) controls four of the disk state-control lines, selects the internal or external drive, and generates the read-data and write-data signals; a VIA provides a fifth state-control line. It runs at 15.6672 MHz, twice the IWM's clock, and software divides the clock by two when it works with an 800K drive or a Hard Disk 20. On the Macintosh IIfx the SWIM is driven by the IOP, which moves disk data between main memory and its own RAM by DMA.[2]
The SWIM can send data to the drive at about 500 kbit/s; the effective rate in GCR mode is about 375 kbit/s.[2]
The SWIM does not support the single-sided drive, so a 400K drive cannot be used on an FDHD Macintosh. Any Macintosh that supports an external FDHD drive can take an external 800K drive instead.[2]
Compatibility
| Model | Internal drives | External drives |
|---|---|---|
| Macintosh SE FDHD | 1 | 1 |
| Macintosh SE/30 | 1 | 1 |
| Macintosh Portable | 1 or 2 | 1 |
| Macintosh IIx | 1 or 2 | 0 |
| Macintosh IIcx | 1 | 1 |
| Macintosh IIci | 1 | 1 |
| Macintosh IIfx | 1 or 2 | 0 |
Macintosh SE computers made before September 1989 use the 800K drive.[2] On a Macintosh, the external SuperDrive handles 1.4 MB disks only if the computer's internal drive can, and only under system software 6.0 or later.[3]
On the Apple II, the external SuperDrive plugs into the disk drive port of the Apple IIGS or Apple IIc Plus, or into a controller card in a IIe or IIGS. A IIe or IIGS needs a special controller card to use 1.4 MB disks.[3] That card is the Apple II 3.5 Disk Controller Card; without it, a SuperDrive on the IIGS's built-in SmartPort reads and writes only 800K disks. On a IIe the card is needed to use the drive at all.[5] Up to four drives can be daisy-chained on an Apple II, with any SuperDrives nearest the computer. Remove the plastic cover from the SuperDrive's rear connector with a flat-bladed screwdriver before chaining a second drive.[3]
Do not put 1.4 MB disks in 400K or 800K drives: they cannot read, write or properly initialise high-density disks. A high-density disk has a second square hole in the case and is marked HD.[3][5]
Internal connectors
The connector designators in Apple's take-apart procedure for the external drive:[6]
| Connector | Goes to |
|---|---|
| CN101 | External drive cable |
| CN102 | Daisy-chain interface board |
| CN104 | LED cable |
| CN105 | Eject button cable |
Disassembly
Apple's procedure, abbreviated:[6]
- Remove the four screws from the case bottom and pull the bottom cover off.
- Remove the floppy metal shield from the drive assembly.
- Pull the cable anchor free of the top case.
- Hold the case top in one hand and the drive assembly in the other, slide the assembly as far as it will go towards the cable end, and lift it out. Turn it over.
- With needle-nose pliers, disconnect CN104 (LED) and CN105 (eject button).
- For the external cable, remove the mounting screw from the external drive shield, pull the shield back and disconnect the cable from CN101. To replace the shield or the cable, separate them by removing the ground screw.
- For the daisy-chain board, disconnect CN102, release the two side tabs to remove the plastic daisy-chain cover from the outer metal shield, then remove the screw holding the board and slide it out.
- For the mechanism, remove the four screws from the outer metal shield, disconnect CN102 from the mechanism, and push the inner metal shield in the direction of the arrow until its tabs clear the holes in the mechanism.
Remove the dust shield from a replacement 1.4 MB mechanism before installing it.[6]
Troubleshooting
Apple's symptom chart lists cures in order of likelihood. Try the first; if the symptom persists, refit the original module before trying the next.[6]
| Symptom | Apple's cures, in order |
|---|---|
| Drive does not come on; LED flashes once or does not light | Drive mechanism, then external drive cable, then LED assembly |
| Reads but does not write | Verify that the drive is a 1.4 MB SuperDrive, then drive mechanism, then external drive cable |
| Does not read but LED comes on | Bad disk, then drive mechanism |
| Does not eject disk | Drive mechanism, then eject switch cable assembly |
| Functions, but LED does not light | LED assembly, then drive mechanism |
| Reads and writes 800K disks but not HD disks | Verify that the drive is a 1.4 MB SuperDrive, then drive mechanism |
| Unable to read; many file-transfer errors | Clean drive, then drive mechanism |
| Fails to format | Clean drive, then drive mechanism |
| An MS-DOS drive does not recognise a disk formatted on a 1.4 MB SuperDrive | Format all disks on the MS-DOS drive first; they can then be read and written in either drive |
Several of these are not drive faults. Apple's first step for a drive that will not write, or will not handle HD disks, is to confirm the drive really is a 1.4 MB SuperDrive.[6] A SuperDrive attached to an Apple IIGS's built-in port handles only 800K disks.[5] The eject button works only with the power on and only on an Apple II; on a Macintosh, or on a IIGS under GS/OS, eject by dragging the disk icon to the Trash. As a last resort a straightened paper clip in the access hole to the right of the slot releases the disk.[3]
Apple's user guide says the mechanism should not need cleaning in normal use and that a drive that consistently fails to read or write should go for service.[3] The Service Source's "clean drive" step does not say how.[6] See Floppy Drive Repair for mechanism work.
Documentation
- Apple SuperDrive/HDI-20 Service Source: Apple's Service Source for the external SuperDrive (troubleshooting and take-apart).
- Apple SuperDrive User's Guide (030-1850-A).
- Apple II 3.5 Disk Controller Card Owner's Guide (030-5717-A).
- Guide to the Macintosh Family Hardware, 2nd edition, Chapter 9: interface, connector pinouts and circuit diagrams.
- Macintosh HDI-20 1.4 MB Drive Service Source: the separate PowerBook HDI-20 external drive.
- Macintosh II Repair and Upgrade Secrets (Larry Pina), chapter 8 "FDHD disk drive upgrades" (p. 189): the FDHD/ROM upgrade for the Macintosh II.
- Apple SuperDrive User's Guide
See also
References
- ↑ Apple Computer, Guide to the Macintosh Family Hardware, second edition, Addison-Wesley, 1990, Chapter 9 "Floppy Disk Interfaces". Hosted as File:Apple Guide to the Macintosh Family Hardware 2nd Edition 1990.pdf.
- ↑ 2.0 2.1 2.2 2.3 2.4 2.5 2.6 Guide to the Macintosh Family Hardware, 2nd ed., pp. 343-345: "the Apple FDHD drive, also called the SuperDrive"; Table 9-6, models that use it and how many internal and external drives each takes; the note that Macintosh SE computers made before September 1989 use the 800K drive; the SWIM (Super Woz Integrated Machine) and its 15.6672 MHz clock; the IOP on the IIfx; the SWIM's lack of support for the single-sided drive; the approximate 500 kbit/s and 375 kbit/s data rates.
- ↑ 3.0 3.1 3.2 3.3 3.4 3.5 3.6 Apple Computer, Apple SuperDrive User's Guide, 030-1850-A, 1991. Hosted as File:Apple SuperDrive Users Guide 1991.pdf.
- ↑ 4.0 4.1 4.2 4.3 Guide to the Macintosh Family Hardware, 2nd ed., p. 330, Table 9-1 "Basic features of Macintosh floppy disk drives", and p. 331, "Data encoding methods".
- ↑ 5.0 5.1 5.2 Apple Computer, Apple II 3.5 Disk Controller Card Owner's Guide, 030-5717-A, 1991, Chapter 1 "Overview", p. 2, and Chapter 4 "Special rules for SuperDrives", pp. 28-29. Hosted as File:Apple II 3.5 Disk Controller Card Owners Guide 1991.pdf.
- ↑ 6.0 6.1 6.2 6.3 6.4 6.5 6.6 6.7 Apple Computer, Apple SuperDrive (Service Source), 21 pp., 1995. Troubleshooting (Symptom Charts pp. 2-4) and Take Apart (Top & Bottom Cover pp. 1-3; External Cable and Shield pp. 4-5; Daisy Chain Interface Board pp. 6-7; 1.4 MB Drive Mechanism pp. 8-10). Hosted as File:Apple superdrive.hdi 20.pdf; see Apple SuperDrive/HDI-20 Service Source.