The
Disk II Floppy Disk Subsystem was a 5¼-inch
floppy disk driveA floppy disk is a data storage medium that is composed of a disk of thin, flexible magnetic storage medium encased in a square or rectangular plastic shell. Floppy disks are read and written by a floppy disk drive or FDD, the initials of which should not be confused with "fixed disk drive," which...
designed by
Steve WozniakStephen Gary "Woz" Wozniak is an American computer engineer who founded Apple Computer, Inc. with Steve Jobs. His inventions and machines are credited with contributing significantly to the personal computer revolution of the 1970s. Wozniak created the Apple I and Apple II computers in...
and manufactured by
Apple ComputerApple Inc. is an American multinational corporation that designs and manufactures consumer electronics and computer software products. The company's best-known hardware products include Macintosh computers, the iPod and the iPhone...
. It was first introduced in 1978 at a retail price of US$495 for pre-order; it was later sold for $595 including the
controller cardThe disk controller is the circuit which allows the CPU to communicate with a hard disk, floppy disk or other kind of disk drive....
and cable. The Disk II was designed specifically for use with the Apple II
personal computerA personal computer is any general-purpose computer whose size, capabilities, and original sales price make it useful for individuals, and which is intended to be operated directly by an end user, with no intervening computer operator...
family to replace the slower cassette tape storage and cannot be used with any Macintosh computer without an
Apple IIe CardThe Apple IIe Card is, in a sense, the smallest AppleII "computer" ever designed, though as a compatibility card it is technically not considered anextension of the Apple II line...
.
The first
Disk II drives (A2M0003) sold were built using parts from
Shugart DrivesShugart Associates was a computer peripheral manufacturer that dominated the floppy disk drive market in the late 1970s and is famous for introducing the minifloppy disk drive....
, but to reduce costs Apple switched to
Alps Electric Co.produces electronic devices, including potentiometers and touchpads. Alps is a multinational corporation, headquartered in Tokyo, Japan. The company was established in 1948. As of 2004, the CEO is Masataka Kataoka. Alps is also well-known for the Alpine brand of car audio.Alps licenses their...
of
Japanis an island country in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, People's Republic of China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...
who built them for half the cost.
The
Disk II Floppy Disk Subsystem was a 5¼-inch
floppy disk driveA floppy disk is a data storage medium that is composed of a disk of thin, flexible magnetic storage medium encased in a square or rectangular plastic shell. Floppy disks are read and written by a floppy disk drive or FDD, the initials of which should not be confused with "fixed disk drive," which...
designed by
Steve WozniakStephen Gary "Woz" Wozniak is an American computer engineer who founded Apple Computer, Inc. with Steve Jobs. His inventions and machines are credited with contributing significantly to the personal computer revolution of the 1970s. Wozniak created the Apple I and Apple II computers in...
and manufactured by
Apple ComputerApple Inc. is an American multinational corporation that designs and manufactures consumer electronics and computer software products. The company's best-known hardware products include Macintosh computers, the iPod and the iPhone...
. It was first introduced in 1978 at a retail price of US$495 for pre-order; it was later sold for $595 including the
controller cardThe disk controller is the circuit which allows the CPU to communicate with a hard disk, floppy disk or other kind of disk drive....
and cable. The Disk II was designed specifically for use with the Apple II
personal computerA personal computer is any general-purpose computer whose size, capabilities, and original sales price make it useful for individuals, and which is intended to be operated directly by an end user, with no intervening computer operator...
family to replace the slower cassette tape storage and cannot be used with any Macintosh computer without an
Apple IIe CardThe Apple IIe Card is, in a sense, the smallest AppleII "computer" ever designed, though as a compatibility card it is technically not considered anextension of the Apple II line...
.
History
The first
Disk II drives (A2M0003) sold were built using parts from
Shugart DrivesShugart Associates was a computer peripheral manufacturer that dominated the floppy disk drive market in the late 1970s and is famous for introducing the minifloppy disk drive....
, but to reduce costs Apple switched to
Alps Electric Co.produces electronic devices, including potentiometers and touchpads. Alps is a multinational corporation, headquartered in Tokyo, Japan. The company was established in 1948. As of 2004, the CEO is Masataka Kataoka. Alps is also well-known for the Alpine brand of car audio.Alps licenses their...
of
Japanis an island country in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, People's Republic of China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...
who built them for half the cost. Early production at Apple was handled by two people, and they produced about thirty drives a day.
Normal storage capacity per disk side was 113.75KB with DOS 3.2.1 and earlier (13 256-byte sectors per track, 35 tracks per side), or 140KB with DOS 3.3 and the accompanying
firmwareIn electronics and computing, firmware is a term often used to denote the fixed, usually rather small, programs and data structures that internally control various electronic devices...
update for the controller card (16 sectors per track). The drive mechanism only contained one read/write head, making it single sided, however it was common for users to manually flip the disk to utilize the opposite side (after cutting a second notch on the diskette's protective shell). Only one side could be accessed at once, but it did essentially double the capacity of each floppy diskette. The full-height drive shipped inside a beige painted metal case and connected via a 20-pin
ribbon cableA ribbon cable is a cable with many conducting wires running parallel to each other on the same flat plane. As a result the cable is wide and flat...
(
DB-19The DB-19 is a D-subminiature connector found on the Apple Macintosh, NeXT and some Atari computers, and is generally used to connect external floppy disk drives or hard drives to the computer....
adapters were eventually available for use with Apple's later connector standard). Up to 6 drives could be used simultaneously with 3 interface cards (2 per card). A Bell & Howell version of the Disk II was also manufactured by Apple in a black painted case which matched the color of the Bell & Howell version of the Apple II Plus which Apple was already manufacturing.
Disk III
In 1978, Apple intended to develop its own
FileWareFileWare floppy disk drives and diskettes were designed by Apple Computer as a higher-performance alternative to the Disk II and Disk III floppy systems used on the Apple II and Apple III microcomputers...
drive mechanism for use in the new Apple /// and
LisaThe Apple Lisa was a personal computer designed at Apple Computer, Inc. during the early 1980s.The Lisa project was started at Apple in 1978 and evolved into a project to design a powerful personal computer with a graphical user interface that would be targeted toward business customers.Around...
business computers being developed. They quickly ran into difficulties which precluded them from being incorporated in the Apple ///, which continued to use the earlier Shugart design.
The first variation of the Disk II introduced for the Apple ///, called the
Disk /// (A3M0004), used the identical drive mechanism inside a modified plastic case with a proprietary connector. With some modification both drives are interchangeable. Though Apple sought to force the purchase of new drives with the Apple ///, many former Apple II users quickly devised a way to adapt their existing and cheaper Disk II drives, however only one external Disk II was supported in this manner. The Disk /// was the first to allow daisy chaining of up to three additional drives to the single 26 pin
ribbon cableA ribbon cable is a cable with many conducting wires running parallel to each other on the same flat plane. As a result the cable is wide and flat...
connector on the Apple ///, for a total of 4 floppy disk drives – the Apple /// was the first Apple to contain a built-in drive mechanism. The Apple III Plus changed its 26-pin connector to a DB-25 connector, which required an adapter for use with the Disk III.
FileWare
In 1983 Apple announced the 860K
FileWareFileWare floppy disk drives and diskettes were designed by Apple Computer as a higher-performance alternative to the Disk II and Disk III floppy systems used on the Apple II and Apple III microcomputers...
drives (
UniFile and
DuoFile) as a replacement for the Disk II & III, but due to the notorious unreliability of the Apple-built so-called "Twiggy" drives first used in the Lisa, the products never shipped.
3.5"
In 1985, Apple attempted to introduce a new 3.5" 800K floppy disk format to eventually replace the Disk II format. However, the external
UniDisk 3.5" drive required a ROM upgrade or a new disk controller card to be used. Many original Apple IIs could not use the new controller without further upgrades as well and therefore the 3.5" format was not widely accepted. Though Apple eventually offered a 1.44MB
SuperdriveSuperDrive is a trademark used by Apple Inc. for two different storage drives: from 1988–1999 to refer to a high-density floppy disk drive capable of reading all major 3.5" disk formats; and from 2001 onwards to refer to a combined CD/DVD reader/writer .-Floppy disk drive:The term was first used by...
as well, the 5.25" Disk II format continued to be offered in preference alongside the newer 3.5" drives until the platform was discontinued in 1993.
DuoDisk
In 1983, along with the introduction of the
Apple IIeThe Apple IIe is the third model in the Apple II series of personal computers produced by Apple Computer. The e in the name stands for enhanced, referring to the fact that several popular features were now built-in that were only available as upgrades and add-ons in earlier models...
, Apple initially offered a combination of two,
two third-heightA drive bay is a standard-sized area for adding hardware to a computer. Most drive bays are fixed to the inside of a case, but some can be removed....
, 143K Disk II drive mechanisms side-by-side in a single plastic case, called the
DuoDisk 5.25 (A9M0108), which could not be daisy chained. The unit was designed to be stacked on top of the computer beneath the monitor. Each unit required its own disk controller card and the number of units was limited to the number of available slots. Originally released with a DB-25 connector, to match that of the Apple III Plus, it was the first to adopt Apple's standard DB-19 floppy drive connector.
UniDisk
Apple later introduced the
UniDisk 5.25" (A9M0104) in a plastic case, which modernized the appearance of the Disk II to better match the
Apple IIeThe Apple IIe is the third model in the Apple II series of personal computers produced by Apple Computer. The e in the name stands for enhanced, referring to the fact that several popular features were now built-in that were only available as upgrades and add-ons in earlier models...
, followed by a matching Platinum-gray version which was renamed
Apple 5.25 Drive (A9M0107), companion to the 800K
Apple 3.5 Drive, and introduced alongside the first Platinum-colored computer the
Apple IIGSThe Apple IIGS, the fifth model inception of the Apple II, is the most powerful member of the Apple II series of personal computers made by Apple Computer...
. Essentially it was a single half-height Disk II mechanism inside an individual drive enclosure. All of these drives introduced a
daisy chainDaisy chain may refer to:*A daisy garland created from daisy flowers *Daisy chain *Daisy chain...
pass-through port. While the drives are essentially interchangeable among Apple II computers, only the Apple 5.25 Drive can be used with the
Apple IIe CardThe Apple IIe Card is, in a sense, the smallest AppleII "computer" ever designed, though as a compatibility card it is technically not considered anextension of the Apple II line...
on a
Macintosh LCThe Macintosh LC was Apple Computer's product family of low-end consumer Macintosh personal computers in the early 1990s. The original Macintosh LC was released in 1990 and was the first affordable color-capable Macintosh. Due to its affordability and Apple II compatibility the LC was adopted...
.
Disk IIc
The
Disk IIc (A2M4050) was a half-height 5.25-inch
floppy disk driveA floppy disk is a data storage medium that is composed of a disk of thin, flexible magnetic storage medium encased in a square or rectangular plastic shell. Floppy disks are read and written by a floppy disk drive or FDD, the initials of which should not be confused with "fixed disk drive," which...
introduced by
Apple ComputerApple Inc. is an American multinational corporation that designs and manufactures consumer electronics and computer software products. The company's best-known hardware products include Macintosh computers, the iPod and the iPhone...
in 1984 styled for use alongside the
Apple IIcThe Apple IIc, the fourth model in the Apple II series of personal computers, was Apple Computer’s first endeavor to produce a portable computer. The end result was a luggable 7½ pound notebook-sized version of the Apple II that could easily be transported from place to place...
personal computer, the only other Apple II to contain a built-in drive mechanism as well. The disk port on the original IIc was only designed to control an external 5.25 disk drive, and as such, this particular drive omitted a daisy-chain port in back. It was possible to use on other Apple II models, so long as it came last in the chain of drive devices (due to lacking a daisy-chain port). Essentially the same as the full-height DIsk II, it offered slightly faster access time. Apple sold the Disk IIc for US$329, and other companies later sold similar drives for less.
Apple PC 5.25" Drive
Not to be confused with the
Apple 5.25 Drive (A9M0110), in 1987 Apple sought to better compete in the
IBMInternational Business Machines Corporation, abbreviated IBM, is a multinational computer technology and IT consulting corporation headquartered in Armonk, Town of North Castle, New York, United States. The company is one of the few information technology companies with a continuous history dating...
dominated business market by offering a means of cross-compatibility. Alongside the release of the
Macintosh SEThe Macintosh SE was a personal computer manufactured by Apple between March 1987 and October 1990. This computer marked a significant improvement on the Macintosh Plus design and was introduced by Apple at the same time as the Macintosh II....
&
Macintosh IIThe Apple Macintosh II was the first personal computer model of the Macintosh II series in the Apple Macintosh line....
, Apple released the
Apple PC 5.25" Drive which required a separate custom
PC 5.25 Floppy Disk Controller Card for each Mac, for use with industry standard 5.25" 360K formatted flexible disks. It was similar in appearance to the Disk IIc. Through the use of special Macintosh
Apple File ExchangeApple File Exchange is a utility included on the Tidbits disk or Install 2 disk in system versions 7.0 through 7.1. In System 7.5, it was replaced by PC Exchange....
utility, the drive could read and write files between Mac and
MS-DOSMS-DOS is an operating system developed by Microsoft. It was the most commonly used member of the DOS family of operating systems and was the main operating system for personal computers during the 1980s. It was preceded by M-DOS , designed and copyrighted by Microsoft in 1979...
formats. Translators could convert documents between
WordStarWordStar was a word processor application, published by MicroPro International, originally written for the CP/M operating system but later ported to DOS, that enjoyed a dominant market share during the early to mid-1980s. Although Seymour I...
and
MacWriteMacWrite was a word processor application released along with the first Apple Macintosh systems in 1984. It was the first such program that was widely available to the public to offer WYSIWYG operation, with multiple fonts and styles...
, among others.
Unfortunately, this drive is not compatible with any Apple II computer or the
Apple IIe CardThe Apple IIe Card is, in a sense, the smallest AppleII "computer" ever designed, though as a compatibility card it is technically not considered anextension of the Apple II line...
for the
Macintosh LCThe Macintosh LC was Apple Computer's product family of low-end consumer Macintosh personal computers in the early 1990s. The original Macintosh LC was released in 1990 and was the first affordable color-capable Macintosh. Due to its affordability and Apple II compatibility the LC was adopted...
, nor will it allow a Macintosh to read or write to 5.25" Apple II formatted disks. This drive was made obsolete by the industry-wide wide adoption of 3.5" disks and was replaced by the Apple FDHD Drive which could not only read and write
DOSMS-DOS is an operating system developed by Microsoft. It was the most commonly used member of the DOS family of operating systems and was the main operating system for personal computers during the 1980s. It was preceded by M-DOS , designed and copyrighted by Microsoft in 1979...
and
WindowsMicrosoft Windows is a series of software operating systems and graphical user interfaces produced by Microsoft. Microsoft first introduced an operating environment named Windows in November 1985 as an add-on to MS-DOS in response to the growing interest in graphical user interfaces...
formats, but Apple II files as well. It is the only 5.25" drive manufactured by Apple exclusively for, and that can be used by the Macintosh.
Disk II Cable Pinout
This table shows the pinout of the original 1979 Disk II controller and newer 1983 Uni/Duo Disk I/O controller (655-0101).
The circuitry of these two controllers are identical. The Disk II header pin numbering is per the Disk II controller card silkscreen and the circuit schematic given in the DOS 3.3 manual. The Uni/Duo Disk D-19 pinout was derived from the controller card and comparison to the circuit schematic of the Disk II controller.
| Disk II Header Pin | Uni/Duo Disk D-19 Pin | Uni/Duo Controller Card Cable Color | Description |
|---|
| 1,3,5,7 |
1,2,3,4 |
Brown,Orange,Green,Violet |
Ground return |
| 2 |
11 |
Red |
Phase 0 stepper motor signal |
| 4 |
12 |
Yellow |
Phase 1 stepper motor signal |
| 6 |
13 |
Blue |
Phase 2 stepper motor signal |
| 8 |
14 |
Grey |
Phase 3 stepper motor signal |
| 9 |
5 |
White |
| 10 |
15 |
Black |
WR_REQ - write request signal |
| 11,12 |
6,16 |
Brown,Red |
5 volt power
| 13,15,17,19 |
7,8 |
Orange,Green |
12 volt power
| 14 |
17 |
Yellow |
ENABLE~ drive enable select signal |
| 16 |
18 |
Blue |
RD_DATA read data signal |
| 18 |
19 |
Grey |
WR_DATA write data signal |
| 20 |
10 |
White |
W_PROT write protect signal |
| x |
9 |
Violet |
No connect? |
- NOTE: Since most signals are shared with both drive 1 and drive 2, the logic in each drive uses the ENABLE~ signal to activate appropriately.
- Pin 14 for Disk II drive 1 and drive 2 have separate enable signals (14a and 14b)
- Pin 17 for Uni/Duo Disk is chained to first drive (drive 1) and second drive (drive 2) is enabled via other logic in the first drive. Perhaps the unused wire on pin 9 (no connect at the controller) is used for this purpose.
See also
- Macintosh External Disk Drive
The Macintosh External Disk Drive was the original of a series of external 3.5" floppy disk drives manufactured and sold by Apple Computer exclusively for the Macintosh series of computers introduced in January, 1984. Later, Apple would unify their external drives to work cross-platform between the...
- Apple ProFile
The ProFile was the first hard drive produced by Apple Computer, initially for use with the Apple III personal computer. The original model had a formatted capacity of 5 MB and connected to a special interface card that plugged into an Apple III slot...
External hard disk
- List of Apple drives
- List of products discontinued by Apple Computer
External links