Macintosh LC family
The Macintosh LC is a family of personal computers designed and sold by Apple Computer, Inc. from 1990 to 1997. Introduced alongside the Macintosh IIsi and Macintosh Classic as part of a new wave of lower-priced Macintosh computers, the LC offered the same overall performance as the Macintosh II for half the price. Part of Apple's goal was to produce a machine that could be sold to school boards for the same price as an Apple IIGS, a machine, successful in the education market. Not long after the Apple IIe Card was introduced for the LC, Apple announced the retirement of the IIGS, as the company wanted to focus its sales and marketing efforts on the LC; the original Macintosh LC was introduced on October 1990, with updates in the form of the LC II and LC III in 1992 and early 1993. These early models all shared the same pizza box form factor, were joined by the Macintosh LC 500 series of all-in-one desktop machines in mid-1993. A total of twelve different LC models were produced by the company, the last of which, the Power Macintosh 5300 LC, was on sale until early 1997.
After Apple co-founder Steve Jobs left Apple in 1985, product development was handed to Jean-Louis Gassée manager of Apple France. Gassée pushed the Apple product line in two directions, towards more "openness" in terms of expandability and interoperability, towards higher price. Gassée long argued that Apple should not market their computers towards the low end of the market, where profits were thin, but instead concentrate on the high end and higher profit margins, he illustrated the concept using a graph showing the price/performance ratio of computers with low-power, low-cost machines in the lower left and high-power high-cost machines in the upper right. The "high-right" goal became a mantra among the upper management, who said "fifty-five or die", referring to Gassée's goal of a 55 percent profit margin; this policy led to a series of more expensive computers. This was in spite of strenuous objections within the company, when a group at Claris started a low-end Mac project called "Drama", Gassée killed it.
Elsewhere at the company, two engineers, H. L. Cheung and Paul Baker, had been working in secret on a pet project, a color Macintosh prototype they called "Spin"; the idea was to produce a low-cost system in the vein of the Apple II, a product that Cheung had worked on at Apple as the head of design. The machine would, in effect, be a smaller Macintosh II with built-in video, no NuBus expansion, a matching RGB monitor similar to the one introduced with the Apple IIgs the year prior; the project changed direction during development, with executives dictating that the machine should have video capabilities and processing power similar to the Macintosh IIci, under development at the time. In early 1989, the prototype was shown Apple executives, who liked the project but felt it was not different enough from existing models to justify further effort, the project was shut down. Around the same time, Apple CEO John Sculley was facing public scrutiny for declining sales, blamed in large part on the company's lack of an inexpensive Macintosh computer.
Amidst promises to the press and investors that a new low-cost Macintosh was on the way, he revived the Spin project with the goal of creating the lowest-priced Macintosh, possible. Gassée pleaded with the team to keep color as a feature of the project, from on the product was known internally by a new code name, "Elsie", a homonym for the "LC" name the computer would be sold as. Elsie prototypes at this point resembled an Apple IIc where the keyboard was integrated into the unit, it had a single 800 KB floppy drive with no hard drive; the team ended up with a problem — the machine was cheap, but it wasn't a good computer because the 68000 CPU was not powerful enough to display color graphics with acceptable performance. By April 1989, it was decided to split the project into three computers -- the Macintosh IIsi, which would have the more powerful 68030 CPU. To keep the price down, Apple cut some corners on performance and features, redesigned components to be less expensive. For example, the external floppy connector, included on the IIsi and Classic was excluded from the LC, as it would save a couple of dollars for the connector.
The integrated keyboard had been dropped by this point. The Macintosh LC was introduced to the market alongside the Macintosh Classic and the Macintosh IIsi. Due to pent-up demand for a low-cost color Macintosh, the LC was a strong seller, in 1992, the original Macintosh LC was succeeded by the LC II; the updated machine replaced the LC's Motorola 68020 processor with a 68030 and increased the soldered memory to 4 MB to make it more suitable for System 7. However, it retained the original LC's 16-bit system bus and 10 MB RAM limit, making its performance the same as the earlier model; the main benefit of the 030 processor in the LC II was the ability to use System 7's virtual memory feature. In spite of this, the new model sold better than the LC. Computer Gaming World in 1990 criticized the LC as too expensive, stating that consumers would prefer a $2,000 IBM PS/1 with VGA graphics to a $3,000 LC with color monitor. Although the Classic was more popular at first, by May 1992 the LC was outselling the Classic (1.2 mi
Quarter inch cartridge tape is a magnetic tape data storage format introduced by 3M in 1972, with derivatives still in use as of 2016. QIC comes in a rugged enclosed package of aluminum and plastic that holds two tape reels driven by a single belt in direct contact with the tape; the tape was 1⁄4-inch wide and anywhere from 300 to 1,500 feet long. Data is written linearly along the length of the tape in one track, or it is serialized and written "serpentine" one track at a time, the drive reversing direction at the end of the tape, each track's data written in the opposite direction to its neighbor. Since the introduction of QIC, it has been used and many variations exist. There is a QIC trade association that publishes QIC standards which include interfaces and logical formats. To a large extent it was the efficiency and openness of this organization which encouraged hardware and software developers to use this type of drive and media; the QIC cartridge is distinguished from other types of tape cartridges by the fact that it contains an endless drive belt, moved at a uniform speed by a motorised capstan.
Since the belt is in contact with the tape, this ensures both that the tape moves at uniform speed, that neutral tension is maintained at all times. This is in contrast to cassette tapes or DATs where the tape is moved past the head by a capstan and pinch wheel, but the takeup reel is driven by a servo motor or slipping clutch; the tape in a QIC cartridge is not physically attached to the reels and is never unwound. This is again different from other cassettes or cartridges, which have some form of clip anchoring on at least one end of the tape. To ensure that the tape is never unwound, each end has a small beginning or end of tape hole, detected by an optical sensor, an "early warning" hole further from each end. If a defective drive—for example with fluff in a sensor—winds the tape past the BOT or EOT marker, the tape will detach from the spool and the cartridge will be unusable unless it is reattached; the design of the QIC tape cartridge is robust: the aluminium baseplate is 1⁄10-inch thick, the robust plastic cover can withstand abuse and impacts that would damage other tape formats.
However, because the tape is belt-driven, seeking back and forth can cause the tape to become unevenly tensioned. It is therefore necessary to periodically retension the cartridge; this is accomplished by winding the tape from beginning to end and back in one operation, allowing the belt to equalize itself. For newer QIC drives that use a SCSI interface, there is a SCSI "RETENSION" command; when the cartridge gets old, the belt may not provide enough friction to turn the takeup spool smoothly. When this happens, the tape will need to be replaced. In some cases a cartridge must be formatted before use; the capability to do this is in the drive rather than the host computer. The first QIC tape format was the 5 7⁄8 inches by 3 7⁄8 inches Data Cartridge format with two internal belt-driven reels and a metal base; the original product, the DC300, holds 200 kilobytes. Various QIC DC recording formats have appeared over the years, including: QIC-11: a four-track format giving 20 MB on a 450 ft DC300XL cartridge QIC-24: nine-track, 45 MB or 60MB on a 450 or 600 ft cartridge QIC-120: 15-track, 125 MB, DC6150 cartridge QIC-150: 18-track, 150 MB, DC6150 cartridge QIC-525: 26-track, 525 MB on a 1020 ft DC6525 cartridge QIC-1350: 30-track, 1.35GB on a DC9135 cartridgeOther QIC DC standards include the QIC-02 and QIC-36 drive interface standards.
QIC DC drives use the QIC-104/111 SCSI and QIC-121 SCSI-2 interfaces. Other Data Cartridge look-alike: 3M DC600HC a preformatted format with 16 tracks on 600 foot DC 600A and with software-based EOT/BOT detection. HP used these in the HP914x type of cartridge drives. Don't try to format or write these on something which isn't compatible - they are not regular data cartridges at all; that cartridge doesn't have a visible-by-eye EOT/BOT marker so a regular QIC drive will unspool the tape from the wheel. Demagnetize them will destroy them; the smaller Minicartridge form-factor was introduced. This is small enough to fit in a 3.5 in drive bay. QIC-40 20 tracks DC2000 mini-cartridge 205 ft. 40MB 20 tracks DC2000XL mini-cartridge 307½ ft. 60MB QIC-80 28 tracks DC2080 mini-cartridge 205 ft. 80MB 28 tracks DC2120 mini-cartridge 307½ ft. 120MBThe QIC-40 and QIC-80 were designed to use the same floppy disk controller as a standard floppy drive, with MFM or RLL encoding. Travan is an evolution of the QIC Minicartridge format, sold for personal computer use.
This version, developed by 3M, uses a wider tape to give higher capacities. SLR is Tandberg Data's name for its line of high-capacity QIC data cartridge drives; as of 2005, Tandberg was the only manufacturer of SLR/QIC drives in the world. The largest SLR drive can hold 70 GB of data. A variant from Sony that uses a wider.315 inch tape and increases the recording density. QIC-Wide drives are backwards compatible with QIC tapes. QIC Extra, a modification to support longer tapes and thus more data by the Verbatim Corporation, was made possible by making the cartridges physically longer to accommodate larger spools. In many cases a standard QIC drive and backup package can use the extended length to store additional data, however in some cases an attempt to reformat a QIC-EX cartridge fails since the time taken to traverse the extra length triggers a timeout in the drive or controlling software intended to det
Macintosh II family
The Macintosh II is a family of personal computers, designed and sold by Apple Computer, Inc. from 1987 to 1993. The Macintosh II was the initial model, representing the high-end of the Macintosh line for the time. Over the course of the next six years, seven more models were produced, culminating with the short-lived Macintosh IIvi and Macintosh IIvx models. Apple retired the Macintosh II name. Unlike prior Macintosh models, which are "all-in-one" designs, the Macintosh II models are "modular" systems which do not include built-in monitors and are expandable. Beginning with the Macintosh II and culminating in the Macintosh IIfx, the Macintosh II family was Apple's high-end line from 1987 until the introduction of the Motorola 68040-based Macintosh Quadra computers in 1991. Expansion was provided by way of NuBus, which become the standard expansion bus for the entire Macintosh line for a decade; the Macintosh II was the first to support color displays and the first to support a screen resolution larger than 512x384.
The Macintosh II is the first to use a Motorola 68000 series processor other than the Motorola 68000. Except for the original Macintosh II which launched the line with a Motorola 68020 clocked at 16 MHz, they used the Motorola 68030 microprocessor after the Motorola 68040 was introduced. Apple would adopt the'040 with the introduction of the Quadra 700 and 900, positioning these models as high-end workstation-class machines for graphics and scientific computing, while positioning the Macintosh II family as a mainstream desktop computer. During the Macintosh II series' lifespan, they rose to become among the most powerful personal computers available. While the Macintosh II series itself was replaced by the Macintosh Centris and Quadra, the Macintosh LC and Performa families continued to use the II's 68030 technology long after the 68040 was introduced and the PowerBook continued to use the'030 into the Power Macintosh era. List of Macintosh models grouped by CPU type List of Macintosh models by case type Mac II Series Index, Low End Mac
The Macintosh SE is a personal computer designed and sold by Apple Computer, Inc. from March 1987 to October 1990. It marked a significant improvement on the Macintosh Plus design and was introduced by Apple at the same time as the Macintosh II; the SE retains the same Compact Macintosh form factor as the original Macintosh computer introduced three years earlier and uses the same design language used by the Macintosh II. An enhanced model, the SE/30 was introduced in January 1989; the Macintosh SE was updated in August 1989 to include a SuperDrive, with this updated version being called the "Macintosh SE FDHD" and the "Macintosh SE SuperDrive". The Macintosh SE was replaced with the Macintosh Classic, a similar model which retained the same central processing unit and form factor, but at a lower price point; the Macintosh SE was introduced at the AppleWorld conference in Los Angeles on March 2, 1987. The "SE" is an acronym for "System Expansion", its notable new features, compared to its similar predecessor, the Macintosh Plus, were: First compact Macintosh with an internal drive bay for a hard disk or a second floppy drive.
First compact Macintosh. First Macintosh to support the Apple Desktop Bus only available on the Apple IIGS, for keyboard and mouse connections. Improved SCSI support with a standard 50-pin internal SCSI connector. Better reliability and longer life expectancy due to the addition of a cooling fan. Upgraded video circuitry that results in a lower percentage of CPU time being spent drawing the screen. In practice this results in a 10-20 percent performance improvement. Additional fonts and kerning routines in the Toolbox ROM Disk First Aid is included on the system diskThe SE and Macintosh II were the first Apple computers since the Apple I to be sold without a keyboard. Instead the customer was offered the choice of the new ADB Apple Keyboard or the Apple Extended Keyboard. Apple produced ten SEs with transparent cases as prototypes for promotional employees, they are rare and command a premium price for collectors. The Macintosh SE shipped with System 4.0 and Finder 5.4. The README file included with the installation disks for the SE and II is the first place Apple used the term "Macintosh System Software", after 1998 these two versions were retroactively given the name "Macintosh System Software 2.0.1".
Processor: Motorola 68000, 8 MHz, with an 8 MHz system bus and a 16-bit data path RAM: The SE came with 1 MB of RAM as standard, is expandable to 4 MB. The logic board has four 30-pin SIMM slots. Video: There is 256 KB of onboard video memory, enabling 512x384 monochrome resolution; the built-in screen has a lower resolution. Storage: The SE can accommodate either one or two floppy drives, or a floppy drive and a hard drive. After-market brackets were designed to allow the SE to accommodate two floppy drives as well as a hard drive, however it was not a configuration supported by Apple. In addition an external floppy disk drive may be connected, making the SE the only Macintosh besides the Macintosh Portable and Macintosh II which could support three floppy drives, though its increased storage, RAM capacity and optional internal hard drive rendered the external drives less of a necessity than for its predecessors. Single-floppy SE models featured a drive-access light in the spot where the second floppy drive would be.
Hard-drive equipped models came with a 20 MB SCSI hard disk. Battery: Located on the logic board is a 3.6 V lithium battery, which must be present in order for basic settings to persist between power cycles. Macintosh SE machines which have sat for a long time have experienced battery corrosion and leakage, resulting in a damaged case and logic board. Expansion: A Processor Direct Slot on the logic board allows for expansion cards, such as accelerators, to be installed; the SE can be upgraded to more than 5 MB with the MicroMac accelerators. In the past other accelerators were available such as the Sonnet Allegro. Since installing a card required opening the computer's case and exposing the user to high voltages from the internal CRT, Apple recommended that only authorized Apple dealers install the cards. Upgrades: After Apple introduced the Macintosh SE/30 in January, 1989, a logic board upgrade was sold by Apple dealers as a high-cost upgrade for the SE, consisting of a new SE/30 motherboard, case front and internal chassis to accommodate the upgrade components.
Easter egg: The Macintosh SE ROM size increased from 64 KB in the original Mac to 256 KB, which allowed the development team to include an Easter Egg hidden in the ROMs. By jumping to address 0x41D89A or reading from the ROM chips it is possible to display the four images of the engineering team. Introduced March 2, 1987: Macintosh SEIntroduced August 1, 1989: Macintosh SE FDHD: Includes the new SuperDrive, a floppy disk drive that can handle 1.4 MB High Density floppy disks. FDHD is an acronym for "Floppy Disk High Density". High-density floppies would become the de facto standard on both the Macintosh and PC computers from on. An upgrade kit was sold for the original Macintosh SE which included new ROM chips and a new disk controller chip, to replace the originals. Macintosh SE 1/20: The name of the Macintosh SE FD
Macintosh Quadra 605
The Macintosh Quadra 605 is a personal computer designed and sold by Apple Computer, Inc. from October 1993 to July 1996. The model names reflect a decision made at Apple in 1993 to follow an emerging industry trend of naming product families for their target customers – Quadra for business, LC for education, Performa for home. Accordingly, the Performa 475 and 476 was sold in department stores and electronics stores such as Circuit City, whereas the Quadra was purchased through an authorized Apple reseller; when introduced, the Quadra 605 was the least expensive new computer in Apple's lineup. The Quadra 605 reuses the Macintosh LC III's pizza box form factor with minor modifications; the Quadra 605 was discontinued in October 1994, the LC 475 variant continued to be sold to schools until July 1996. Apple offered no direct replacement for these machines, making it the final Macintosh to use the LC's lightweight slim-line form factor. Apple would not release another desktop computer under 10 pounds until the Mac Mini, nearly ten years later.
All models come standard with a 68LC040 CPU running at 25 MHz, 4 MB RAM on board, 512 KB of VRAM, 1 LC III-style Processor Direct Slot, 1 ADB and 2 serial ports, external SCSI port, a manual-inject floppy drive. Introduced October 18, 1993: Macintosh Performa 475: 4 MB RAM, 160 MB HDD. Bundled with a keyboard and Apple Color Plus 14" Display. Macintosh Performa 476: 4 MB RAM, 230 MB HDD. Bundled with a keyboard and Apple Color Plus 14" Display. Introduced October 21, 1993: Macintosh Quadra 605: 4 MB RAM, 80 MB HDD. Different case design, the only variant that does not have a case screw. Not available in Europe. Macintosh LC 475: 4 MB RAM, 80 MB HDD. Bundled with a keyboard and optionally with an Apple Macintosh Color Display. Central processing unit: 25 MHz MC68LC040, 32-bit bus. 8 KB of on-chip L1 cache is divided into 4 KB of instruction cache. There are no other caches; the 68LC040 can be replaced with a 68040. This will triple the speed of floating point operations. Random access memory: 4 MB on the motherboard, one 72-pin SIMM socket for 80 ns or faster SIMMs.
The official supported maximum RAM is 36 MB in one 32 MB 72-pin SIMM plus 4 MB on the motherboard, but larger SIMMs do work—up to 128 MB may be used, with some limits on RAM type. Physical limits might apply if the side of the SIMM facing the CPU has thicker chips, as the clips on the SIMM socket will not close around it automatically, it should be possible to manually push the clips enough to hold the SIMM in place. The DJMEMC memory controller used in the Quadra 605's predecessors will only recognize SIMMs up to 32 MB, while the newer MEMCjr used in the Quadra 605 recognizes the larger sizes. Video: Video out is provided by one DA15F connector, is compatible with VGA monitors through the use of an adaptor. Two internal Video RAM slots can take either two 256 KB 80 ns 68-pin VRAM SIMMs, or two 512 KB SIMMs. Installing one 512 KB and one 256 KB VRAM SIMM garbles the display. Resolutions and colors available with the two VRAM configurations are shown in the table below: Audio: Out: stereo 8-bit, 11 kHz or 22 kHz.
The input socket is a stereo socket, can input two channels of a stereo signal—however, these are mixed and only accessible to the hardware as a combined mono 8-bit signal. An Apple PlainTalk Microphone provides line-level input by using a longer 4-contact plug which receives power from a 5 V supply within the input jack. Other microphones only give a mic-level input, do not work with the Quadra 605. Recording is possible at 11,000 or 22,000 samples/second, with filters applied at 3.5 kHz and 7 kHz while recording. Floppy Drive: 1.4 MB SuperDrive, manual-inject. Hard Drive: 80 MB, 160 MB or 230 MB SCSI hard drive, depending on model. Battery: Quadra 605s take a lithium half-AA cell 3.6 V battery. If the battery is drained, the video will not start up. To start up a Quadra 605 with a flat or missing battery, it can be turned on for a few seconds turned off for a second on again; this leaves enough charge in the system's capacitors for video to start up. Power supply: 30 watts standard, but many second-hand machines come with replacement PSUs, either third-party, Apple replacement, or stripped from earlier LC models.
Some of these go up to 45 watts. The Quadra 605 is a registered Energy Star-Compliant product. Weight: 8.8 lb / 4 kg standard. A Quadra 605 can support a monitor up to 35 lb / 15.9 kg. Dimensions: 2.9" high x 12.2" wide x 15.3" deep / 7.4 cm high x 31 cm wide x 38.8 cm deep. The Quadra 605 contains. While this is mechanically compatible with previous models' LC PDS it is not a true LC PDS, but emulates the previous machine's 68030 slot. Due to the success of the LC PDS in earlier Macs and with many expansion options manufactured, Apple kept the same slot type in these 68040 machines. While the Quadra 605's LC PDS is 68030-compatible, expansion cards made for'030 processors, such as 68881 or 68882 FPUs, will not work. In addition it can utilize the Apple IIe Card; the Quadra 605 has one SCSI bus, with a 50-pin internal connector (with space for one low-profile 3.5" SC
Small Computer System Interface is a set of standards for physically connecting and transferring data between computers and peripheral devices. The SCSI standards define commands, electrical and logical interfaces. SCSI is most used for hard disk drives and tape drives, but it can connect a wide range of other devices, including scanners and CD drives, although not all controllers can handle all devices; the SCSI standard defines command sets for specific peripheral device types. The ancestral SCSI standard, X3.131-1986 referred to as SCSI-1, was published by the X3T9 technical committee of the American National Standards Institute in 1986. SCSI-2 was published in August 1990 as X3. T9.2 / 86-109, with subsequent adoption of a multitude of interfaces. Further refinements have resulted in improvements in performance and support for ever-increasing storage data capacity. SCSI is derived from "SASI", the "Shugart Associates System Interface", developed circa 1978 and publicly disclosed in 1981. Larry Boucher is considered to be the "father" of SASI and SCSI due to his pioneering work first at Shugart Associates and at Adaptec.
A SASI controller provided a bridge between a hard disk drive's low-level interface and a host computer, which needed to read blocks of data. SASI controller boards were the size of a hard disk drive and were physically mounted to the drive's chassis. SASI, used in mini- and early microcomputers, defined the interface as using a 50-pin flat ribbon connector, adopted as the SCSI-1 connector. SASI is a compliant subset of SCSI-1 so that many, if not all, of the then-existing SASI controllers were SCSI-1 compatible; until at least February 1982, ANSI developed the specification as "SASI" and "Shugart Associates System Interface. A full day was devoted to agreeing to name the standard "Small Computer System Interface", which Boucher intended to be pronounced "sexy", but ENDL's Dal Allan pronounced the new acronym as "scuzzy" and that stuck. A number of companies such as NCR Corporation and Optimem were early supporters of SCSI; the NCR facility in Wichita, Kansas is thought to have developed the industry's first SCSI controller chip.
The "small" reference in "small computer system interface" is historical. Since its standardization in 1986, SCSI has been used in the Amiga, Apple Macintosh and Sun Microsystems computer lines and PC server systems. Apple started using the less-expensive parallel ATA for its low-end machines with the Macintosh Quadra 630 in 1994, added it to its high-end desktops starting with the Power Macintosh G3 in 1997. Apple dropped on-board SCSI in favor of IDE and FireWire with the Power Mac G3 in 1999, while still offering a PCI SCSI host adapter as an option on up to the Power Macintosh G4 models. Sun switched its lower-end range to Serial ATA. Commodore included SCSI on the Amiga 3000/3000T systems and it was an add-on to previous Amiga 500/2000 models. Starting with the Amiga 600/1200/4000 systems Commodore switched to the IDE interface. Atari included SCSI as standard in its Atari MEGA Atari TT and Atari Falcon computer models. SCSI has never been popular in the low-priced IBM PC world, owing to the lower cost and adequate performance of ATA hard disk standard.
However, SCSI drives and SCSI RAIDs became common in PC workstations for video or audio production. Recent physical versions of SCSI—Serial Attached SCSI, SCSI-over-Fibre Channel Protocol, USB Attached SCSI —break from the traditional parallel SCSI bus and perform data transfer via serial communications using point-to-point links. Although much of the SCSI documentation talks about the parallel interface, all modern development efforts use serial interfaces. Serial interfaces have a number of advantages over parallel SCSI, including higher data rates, simplified cabling, longer reach, improved fault isolation and full-duplex capability; the primary reason for the shift to serial interfaces is the clock skew issue of high speed parallel interfaces, which makes the faster variants of parallel SCSI susceptible to problems caused by cabling and termination. The non-physical iSCSI preserves the basic SCSI paradigm the command set unchanged, through embedding of SCSI-3 over TCP/IP. Therefore, iSCSI uses logical connections instead of physical links and can run on top of any network supporting IP.
The actual physical links are realized on lower network layers, independently from iSCSI. Predominantly, Ethernet is used, of serial nature. SCSI is popular on high-performance workstations and storage appliances. All RAID subsystems on servers have used some kind of SCSI hard disk drives for decades, though a number of manufacturers offer SATA-based RAID subsystems as a cheaper option. Moreover, SAS offers compatibility with SATA devices, creating a much broader range of options for RAID subsystems together with the existence of nearline SAS drives. Instead of SCSI, modern desktop computers and notebooks use SATA interfaces for internal hard disk drives, with M.2 and PCIe gaining popularity as SATA can bottleneck modern solid-state drives. SCSI is available in a variety of int
The Macintosh 512K enhanced was introduced in April 1986 as a cheaper alternative to the top-of-the-line Macintosh Plus, which had debuted three months previously. It is the same as the Macintosh 512K but with the 800K disk drive and 128K of ROM used in the Macintosh Plus. Like its predecessors, it has little room for expansion; some companies did create memory upgrades. It is the earliest Macintosh model able to run System Software 6, it is the earliest that can be used as an AppleShare server and, with a bridge Mac, communicate with modern devices. The case was identical to its predecessor, except for the model number listed on the rear bucket's agency approval label, it used the same beige-like color as well. But like the Macintosh Plus, in 1987 the 512Ke adopted the standard Apple "Platinum" color, as well as the same case-front design as the Plus, though keeping its original rear bucket. In its lifespan, the 512Ke was discounted and offered to the educational market, badged as the Macintosh ED.
The 512Ke shipped with the original short Macintosh Keyboard, but the extended Macintosh Plus Keyboard with built-in numeric keypad could be purchased optionally. A version of the 512Ke only sold outside of North America included the full keyboard and was marketed as the Macintosh 512K/800; the larger keyboard would be included as standard in North America as well. Although the 512Ke includes the same 128K ROMs and 800K disk drive as the Mac Plus, the 512Ke retains the same port connectors as the original Mac. For this reason, 512Ke users' only hard disk option is the slower, floppy-port-based Hard Disk 20, or similar products for the serial port though the 512Ke ROMs contain the "SCSI Manager" software that enables the use of faster SCSI hard disks. Apple did point users to certain third-party products which could be added to the 512Ke to provide a SCSI port. A Macintosh 512K could be upgraded to a 512Ke by purchasing and installing Apple's $299 Macintosh Plus Disk Drive Kit; this included the following: 800 KB double-sided floppy disk drive to replace the original 400 KB single-sided drive 128 KB ROM chips to replace original 64 KB ROM Macintosh Plus System Tools disk with updated system software Installation guideOne further upgrade made by Apple replaced the logic board and the rear case with those of the Macintosh Plus, providing built-in SCSI functionality and up to 4MB RAM.
Because Apple's official upgrades were costly, many third-party manufacturers offered add-on SCSI cards, as well as RAM upgrades, to achieve the same functionality. The new ROM allowed the computer to run application software. After June 1986, the 512Ke shipped with System 3.2. After it was discontinued, Apple changed the recommended OS for the 512Ke to System 4.1. System 6.0.8 is the maximum OS for the 512Ke. Macintosh 128K/512K technical details Inside the Macintosh 512K