Developer | Apple Computer |
---|---|
Type | Disk Drive |
Release date | May 4, 1984 |
Introductory price | US$495 |
The Macintosh External Disk Drive is the original of a series of external 31⁄2-inch 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 Macintosh and Apple II product lines, dropping the name 'Macintosh' from the drives. Though Apple had been producing external floppy disk drives prior to 1984, they were exclusively developed for the Apple II, III and Lisa computers using the industry standard 51⁄4-inch flexible disk format. The Macintosh external drives were the first to widely introduce Sony's new 31⁄2-inch rigid disk standard commercially and throughout their product line. Apple produced only one external 31⁄2-inch drive exclusively for use with the Apple II series called the Apple UniDisk 3.5.
400K[edit]
The original Macintosh External Disk Drive (M0130) was introduced with the Macintosh on January 24, 1984. However, it did not actually ship until May 4, 1984, sixty days after Apple had promised it to dealers. Bill Fernandez was the project manager who oversaw the design and production of the drive.[1] The drive case was designed to match the Macintosh and included the same 400-kilobyte drive (a Sony-made 31⁄2-inch single-sided mechanism) installed inside the Macintosh. Although very similar to the 400-kilobyte drive which newly replaced Apple's ill-fated Twiggy drive in the Lisa, there were subtle differences relating mainly to the eject mechanism. However, confusingly all of these drives were labelled identically. The Macintosh could only support one external drive, limiting the number of floppy disks mounted at once to two, but both Apple and third party manufacturers developed external hard drives that connected to the Mac's floppy disk port, which had pass-through ports to accommodate daisy-chaining the external disk drive. Apple's Hard Disk 20 could accommodate an additional daisy-chained hard drive as well as an external floppy disk.
3.5-inch single-sided floppies had been used on several microcomputers and synthesizers in the early 1980s, including the Hewlett Packard 150 and various MSX computers. The standard on all of these was MFM with 80 tracks and 9 sectors per track, giving 360 kB per disk. However, Apple's custom interface uses Group Coded Recording (GCR) and a unique format which puts fewer sectors on the smaller inner tracks and more sectors on the wider outer tracks of the disk. The disk speeds up when accessing the inner tracks and slows down when accessing the outer ones. This is called the 'Zoned CAV' system; there are five zones of 16 tracks each, the inner most zone had 8 sectors per track, the next zone 9 sectors per track, and so on; the outermost zone has 12 sectors per track. This allows more space per disk (400 kB) and also improves reliability by reducing the number of sectors on the inner tracks which had less physical media to allocate to each sector.
The external 400-kilobyte Macintosh drive will work on any Macintosh that does not have a high density SuperDrive controller (due to electrical changes with the interface), but the disks in practice only support the MFS file system. Although a 400-kilobyte disk may be formatted with HFS, it cannot be booted from, nor is it readable in a Mac 128/512.
Formatta Filler 7.0 For Mac Macintosh Hard Disk 20 Model M0135 For Mac Rme 400 Driver For Mac Dvc 130 Driver For Mac Gecko Iphone Toolkit Free Download For Mac Greenchess For Mac Spl Vitalizer Mk2-t (free Version Download For Mac Wavepad Free Audio And Music Editor For Mac N64 Emulator Mac Os X 10.6.8. May 09, 2019 The Best External Hard Drives and SSDs for Mac in 2020. Looking to add storage, or for a smart way to back up your Mac? Here's what you need to know, along with our top-rated Apple-friendly drives.
![Macintosh hard disk 20 model m0135 for mac download Macintosh hard disk 20 model m0135 for mac download](https://i.ebayimg.com/images/g/i80AAOSwxs1eL3B6/s-l400.jpg)
Copy protection schemes were not as elaborate or widespread on Macintosh software as they were on Apple II software for several reasons. First, the Mac drives did not afford the same degree of low-level control. Also Apple did not publish source listings for the Mac OS ROMs as they did with the Apple II. Finally, the Mac OS routines were considerably more complex and disk access had to be synchronized with the mouse and keyboard.
800K[edit]
By early 1985, it was clear that the Macintosh needed additional storage space, in particular a hard drive. Apple announced their first hard drive for the Mac in March 1985. However, the MFS file system did not support subdirectories, making it unsuitable for a hard disk. Apple quickly began adopting for the Mac the hierarchical based SOS filing system introduced with the Apple III and long since implemented in ProDOS for the Apple II series and the Lisa. This change in the Mac's filing system delayed the introduction of the double sided Sony drives which Apple intended to offer as soon as the technology was available, a concession they made when adopting the Sony drives over their own problematic double-capacity Twiggy drives.[2][3] However, based on the success of the 3.5-inch floppy drive for the Mac, there was no such obstacle in immediately implementing an 800-kilobyte drive for the Apple II, so it was introduced in September 1985, four months before the version for the Mac. While Apple simultaneously introduced their new hard drive after a 6-month delay, they chose not to implement the new floppy drive for the Macintosh at that time.
Apple UniDisk 3.5[edit]
In September 1985, Apple released its first 31⁄2-inch drive (A2M2053) for the Apple II series utilizing Sony's new 800-kilobyte double-sided drive mechanism which would not be released for the Macintosh until 4 months later. The Apple UniDisk 3.5 drive contained additional circuitry making it an 'intelligent' or 'smart' drive; this made it incompatible with the Macintosh, despite having the identical mechanism that was to be later used in the Macintosh drive. However, if the internal circuit board (which consisted of its own CPU, IWM chip, RAM and firmware) was bypassed it could operate on a Macintosh as an 800-kilobyte drive.[4] This permitted storage-hungry Mac users the ability to double their disk capacity 5 months before Apple officially made an 800-kilobyte drive available for the Mac. At the time, the HD20 Startup disk came with HFS and a new .Sony driver that supported 800k drives (in addition to the HD20). Ironically, though the drive would prove to be significantly faster than the previous 400-kilobyte drive, it was specifically slowed down to accommodate the slower 1-megahertz processor of the Apple II. It came in the Snow White-styled case and color to match the Apple IIc and had a pass-through connector for the addition of a second daisy-chained drive. It plugged in directly to the Apple IIc disk port (although original IIcs needed a ROM upgrade) and required a specialized interface card on earlier Apple II models. It would later also work directly with the built-in disk port on the Apple IIc Plus and Apple IIGS through backwards compatibility. This was not recommended for the latter two machines as the Apple 3.5' Drive was faster. It continued to be sold for use with the Apple IIc and IIe which could not use the subsequent replacement Apple 31⁄2-inch drive, until the Apple IIc Plus redesign in 1988 and Apple II 3.5 Disk Controller Card released in 1991. Apple developed a DuoDisk 3.5 which contained two drives vertically stacked, but never brought it to market. The 31⁄2-inch format was not very popular in the Apple II community (excluding the 16-bit Apple IIGS) as most software was released in the 5.25-inch format to accommodate the existing installed Disk II drives.
Macintosh 800K External Drive[edit]
In January 1986, Apple introduced the Macintosh Plus which had a Sony double-sided 800-kilobyte capacity disk drive, and used the new HFS disk format providing directories and sub-directories. This drive was fitted into an external case as the Macintosh 800K External Drive (M0131), which was slimmer than the earlier 400-kilobyte drive. It could be used with Macintosh models except for the original 128K, which could not load the HFS disk format. The drive supported the older 400-kilobyte single-sided disks allowing them to be shared. The use of Apple's GCR with variable speed (as used on the 400-kilobyte drive) accommodated a higher storage capacity than its 720-kilobyte PC counterparts. In addition, the mechanism was much quieter and significantly faster than its predecessor. Designed primarily to run on Macs with the new 128-kilobyte ROM which contained the necessary code to support the drive, it could be used with Macs with older 64-kilobyte ROMs if the proper software was loaded from the system folder of a Hard Disk 20 into the Mac's RAM. The drive controlled its own speed and was no longer dependent on an external signal from the Mac, which was blocked on the early drive mechanisms compatible only with the Macintosh. Later universal mechanisms, first used on the Apple II to accommodate proprietary signals, required special cables to isolate the speed signal from the Mac, to prevent damage to the drive. However, with its increased storage capacity combined with 2-4 times the RAM available on the Mac Plus, the external drive was less of a necessity than it had been with its predecessors. Nevertheless, with the only option for adding additional storage being extremely expensive hard drives, a year later Apple increased the maximum number of floppy drives that could be accessed simultaneously to three on the Macintosh SE (the Macintosh Portable was the only other Mac to do so).
Apple 3.5' Drive[edit]
Beginning in September 1986, Apple adopted a unified cross-platform product strategy essentially eliminating platform-specific peripherals where possible. The Apple 3.5' Drive (A9M0106), is an 800K external drive released in conjunction with the Apple IIGS computer, and replaced the beige-colored Macintosh 800K External Drive. It works on both the Apple IIGS as well as the Macintosh. It came in a case similar to the UniDisk, but in Platinum gray. Like the UniDisk 3.5, the Apple 3.5' Drive includes Apple II-specific features such as a manual disk eject button and a daisy-chain connector which allows two drives to be connected to an Apple II computer. The Macintosh however could still only accommodate one external drive, and ignores use of the eject button. Unlike the Macintosh 800K External Drive, the Apple 3.5' Drive can be used natively with the 64-kilobyte ROM stock Macintosh 128K & 512K computers without the HD20 INIT, albeit only with 400K MFS formatted disks. Designed as a universal external drive replacement, the Apple 3.5' Drive was eventually made compatible with the remaining Apple II models in production upon the introduction of the Apple IIc Plus and the Apple II 3.5 Disk Controller Card for the Apple IIe.
1.44MB[edit]
Following the success of the Macintosh implementation of the 31⁄2-inch format, the format was also adopted widely by the personal computer industry. However most of the industry adopted a different Modified Frequency Modulation (MFM) formatting scheme at a fixed rotational speed, incompatible with Apple's own GCR with variable speed, resulting in a less-expensive drive, but with a lower capacity (720 KB rather than 800 KB). In 1987 a newer and better, MFM-based, 'high-density' format was developed which IBM first introduced in their PS/2 systems, doubling the previous storage capacity to 1.4 MB. In Apple's pursuit of cross-compatibility with DOS and Windows-based systems to attract more business customers, they adopted the new format, thus confirming it as the first industry-wide floppy disk standard. However, Apple could not take advantage of the less expensive fixed-speed systems of the IBM-based computers, due to its backward incompatibility with their own variable-speed formats.
Apple FDHD Drive[edit]
Later renamed the Apple SuperDrive (G7287), the Apple FDHD Drive (Floppy Disk High Density) was introduced in 1989 as Apple's first external 1.44 MB high-density double-sided 31⁄2-inch floppy drive. It supported all of Apple's 3.5' floppy disk formats as well as all standard PC formats (e.g. MS-DOS, Windows), allowing the Macintosh to read and write all industry standard floppy disk formats. The external drive was offered only briefly with support for the Apple II, coming late in that product's life. To take advantage of the drive's extended storage and new capabilities, it required the new SWIM (Sander-Wozniak Integrated Machine) floppy disk controller chip to be present on the Macintosh and Apple II, the latter requiring the Apple II 3.5 Disk Controller Card which integrated the chip. Waldorf blofeld license sl hack. If the drive was connected to an older Macintosh, Apple IIGS or Apple IIc Plus with the older IWM (Integrated Woz Machine) chip, the drive would act as a standard 800K drive, without any additional capabilities. The interface card was necessary for the Apple IIGS to make use of its greater storage capacity and ability to handle PC formats. The Apple IIe could not utilize the drive in any form, unless it had the specialized interface card installed, much like the UniDisk 3.5 which the SuperDrive replaced. The last Mac it could be used with was the Classic II and was discontinued shortly thereafter. The drive was fitted in every desktop Mac from its introduction and was eliminated with the introduction of the iMac in 1998. PowerPC Macs dropped the original auto-inject Sony drives and went to a manual inject mechanism.
Macintosh HDI-20 External 1.4MB Floppy Disk Drive[edit]
Manufactured exclusively for use with the Macintosh PowerBook line, the Macintosh HDI-20 External 1.44MB Floppy Disk Drive (M8061) contained a low-powered, slimmer version of the SuperDrive and used a small square HDI-20[5] proprietary connector, rather than the larger standard DE-19 desktop connector, and was powered directly by the laptop. It had a matching dark gray case and an access cover which flipped down to form a stand. The external drive was sold optionally for those PowerBooks which had no built-in drive, however, the identical drive mechanism was included internally in some PowerBook models, which otherwise had no provision to accommodate an external drive.
Macintosh PowerBook 2400c Floppy Disk Drive[edit]
Ak 47 serial numbers romanian. Compatible only with the PowerBook 2400c, the Macintosh PowerBook 2400c Floppy Disk Drive (M4327) used a unique Molex connector [6] rather than the previous HDI-20 connector. Possibly because of the 2400c's IBM design heritage, both the drive and computer use the same connectors as IBM ThinkPad external floppy drives from the same period; however, IBM drives are not electrically compatible.[7]The drive was discontinued in 1998, and would be the last external floppy drive manufactured by Apple.
See also[edit]
References[edit]
- ^Bill Fernandez Portfolio
- ^MacTech Mousehole Vol 1, Issue 5, Letters, Rumor Mill at the Expo
- ^[1] Folklore.org: Macintosh Stories: Quick, Hide In This Closet!
- ^Naiman, Arthur (1987). The Macintosh Bible. Goldstein & Blair. p. 253. ISBN0-940235-00-5.
- ^HDI-20
- ^'PowerBook 2400c Developer Note'(PDF). Archived from the original on July 21, 2004. Retrieved September 30, 2016.CS1 maint: BOT: original-url status unknown (link)
- ^'2400c questions: Sound + PCMCIA Ethernet'. 68kMLA Forums. Retrieved September 30, 2016.
External links[edit]
- Macintosh: Support for External Floppy Drives (at Apple support site)
- vintagemacworld.com Apple External Drives
Retrieved from 'https://en.wikipedia.org/w/index.php?title=Macintosh_External_Disk_Drive&oldid=968109803'
Connects to | Macintosh Plus; Macintosh 512K via:
|
---|---|
Design firm | Apple Inc. |
Manufacturer | Apple Inc. |
Introduced | September 17, 1985 |
Discontinued | September 1987 |
Cost | US$1,495 (equivalent to $3,554 in 2019) |
Type | Hard Disk |
Memory | 20 MB |
Connection | Floppy drive port at 500 kbit/s[1][2] |
Power consumption | 30 W |
Weight | 7 lbs (3.2 kg) |
Dimensions | 3.1 x 9.7 x 10.5 inches (7.9 x 25 x 27 cm) |
The Macintosh Hard Disk 20 was the first hard drive developed by Apple Computer specifically for use with the Macintosh 512K. Introduced on September 17, 1985, it was part of Apple's long-awaited solution toward completing the Macintosh Office (a suite of integrated business hardware & software) announced in January 1985. It would be over a year more before Apple would release the file server software AppleShare that would link all of the hardware together. By that time the SCSI interface introduced on the Macintosh Plus in January 1986, would accommodate far faster and more efficient hard drives, rendering the Hard Disk 20 virtually obsolete.[3]
Features[edit]
The Hard Disk 20 (or HD20, as it was known colloquially) contained a 20 MB 3.5' Rodimehard disk which provided over 50 times the data storage of the stock 400 kB disk drive. At the time when the average file size was around 10-20 kB and due to the vast number of those files the HD 20 could contain, Apple's original Macintosh File System, which did not allow for directories, would have made organizing those files unwieldy. Therefore, Apple introduced it with a new System and Finder update which included the brand new Hierarchical File System allowing the user to better organize files on such a large volume. As a result, only the Macintosh 512K could access it; the original Macintosh 128K did not have enough RAM to load the new file system. In fact, even for the Macintosh 512K to use the drive, it required an additional file in the System Folder on a special startup disk which added additional code into memory during startup. An ingenious startup routine also allowed the Mac to check for the presence of a System file on the Hard Disk, switch over to it and eject the startup disk. Unfortunately, the HD 20 could not be used as a startup disk directly without first loading the code from the floppy disk drive. With the release of the Macintosh Plus and the Macintosh 512Ke, both containing the upgraded 128 kB ROM which contained the additional code, the HD 20 could finally be used alone as a startup disk.
The drive had a rotational speed of 45.73 rotations/second (2744 rpm) and access time of 85 ms.[2]
While other hard drives were available on the market, Apple's HD 20 was generally preferred mainly because Apple broke their own development rules when they offered it. Originally the Macintosh was designed with two serial ports which were to meet all the expansion needs of the user. It also included a dedicated floppy disk port for one external floppy disk. Most of the hard drives which were available on the market used the slower serial port to transfer data per Apple's specifications. Apple instead engineered the HD 20 to use the faster floppy disk port, enabling the user to daisy-chain an external floppy disk drive as well as an additional HD 20. With few exceptions, this along with complete compatibility with the new Hierarchical File System, gave Apple an instant edge over the competition. In addition, the HD 20 had a convenient 'zero-footprint' design which fit precisely underneath the Macintosh, merely elevating it 3 inches, but otherwise taking up no more desk-space.[4]
History[edit]
In 1985, the HD 20 was an important step to solidifying the Macintosh as a true business computer and it was eagerly anticipated following its April announcement. Until Apple's introduction a year later of the Hard Disk 20SC, the first SCSI drive they manufactured, the HD 20 was the only Apple-manufactured hard drive available for any Macintosh except the Macintosh XL. The HD20 was not compatible with any other Apple computer or other platforms.
However, the HD 20's unique design and position in the marketplace was quickly outmoded by the advancement of the significantly faster SCSI standard which also debuted with the Macintosh Plus in January 1986. Some third party companies offered a SCSI conversion kit which replaced the controller board thus preserving the user's investment in the expensive but proprietary Rodime drive.[5] Apple officially dropped support for the HD 20 with System 6 as well as omitting the necessary ROM code beginning with the Macintosh II.[6] Sales of the HD 20 continued to support the Macintosh 512Ke which had no other hard drive options until it was discontinued in late 1987. Apple quickly dropped support for the HD 20 in all of its newer Macs, only to find many business users upgrading their older systems needed a way to transfer data from the unsupported drives to the newer Macs. Only Macs with legacy technology and floppy disk ports, which were eliminated entirely from Macintosh computers in 1991, were able to continue to use the older slower technology.
Manufactured in significant numbers for almost two years, the HD 20 remains as one of the few surviving hard drives a stock Macintosh 512K or 512Ke can use.
See also[edit]
References[edit]
- ^'The Mac Plus 30 Years On'. January 24, 2016. Retrieved April 20, 2016.
- ^ ab'Apple brand HD20, HD20 SC Info'. 2010. Retrieved April 20, 2016.
- ^Macintosh 128K and 512K: SCSI Hard Drives
- ^Lewis, Peter H (October 8, 1985). 'Peripherals; Apple gives its Macintosh a hard disk'. New York Times. Retrieved December 30, 2007.
- ^Apple HD-20: How To Convert It Into A SCSI Device
- ^System 6.0.3: Incompatible with Macintosh 512Ke and HD20
Macintosh Hard Disk 20 Model M0135 For Mac Pro
![Macintosh hard disk 20 model m0135 for mac os Macintosh hard disk 20 model m0135 for mac os](https://i.stack.imgur.com/unR9K.jpg)
External links[edit]
Macintosh Hard Disk 20 Model M0135 For Mac Os
- Hard Disk 20 technical specifications at apple.com at the Wayback Machine (archived May 16, 2011)
- Mac Systems Compatible with Hard Disk 20 at apple.com
- Hard Disk 20 tutorial at VintageMacWorld.com
- Hard Disk 20 Info at Mac512.com's Classic Macintosh Preservation area at the Wayback Machine (archived February 20, 2007)
- The M0001 Registry Owners of Vintage Macintosh
Retrieved from 'https://en.wikipedia.org/w/index.php?title=Hard_Disk_20&oldid=934875896'