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| Also known as | M0001W |
|---|---|
| Manufacturer | Apple Computer |
| Product family | Compact Macintosh |
| Release date | September 10, 1984; 41 years ago (1984-09-10) |
| Introductory price | US$3,195 (equivalent to $9,670 in 2024)[1] |
| Discontinued | April 14, 1986 (1986-04-14) |
| Operating system | 1.0,1.1,2.0,2.1,3.0,3.2,[2]3.3,3.4,4.0,4.1 |
| CPU | Motorola 68000 @7.8338 MHz(Effectively 6 MHz) |
| Memory | 512KB RAM (built-in) |
| Display | 9 in (23 cm) monochrome, 512 × 342 |
| Predecessor | Macintosh 128K |
| Successor | Macintosh 512Ke Macintosh Plus |
| Related | Macintosh XL |
TheMacintosh 512K is apersonal computer that was designed, manufactured and sold byApple Computer from September 1984 to April 1986. It is the first update to the originalMacintosh 128K. It was virtually identical to the previousMacintosh, differing primarily in the amount of built-inrandom-access memory. The increased memory turned the Macintosh into a more business-capable computer and gained the ability to run more software. It is the earliest Macintosh model that can be used as an AppleShare server and, with a bridge Mac, communicate with modern devices.[3]
The Mac 512K originally shipped with Macintosh System 1.1 but was able to run all versions ofMac OS up to System 4.1. It was replaced by theMacintosh 512Ke and theMacintosh Plus. All support for the Mac 512K was discontinued on September 1, 1998.
Like the Macintosh 128K before it, the 512K contained aMotorola 68000 connected to 512 KB ofDRAM by a16-bitdata bus. Though the memory had been quadrupled, it could not be upgraded. The large increase earned it the nicknameFat Mac. A 64 KBROM chip boosts the effective memory to 576 KB, but this is offset by the display's 22 KBframebuffer, which is shared with theDMA video controller. This shared arrangement reduces CPU performance by up to 35%. It shared a revised logic board with the rebadged Macintosh 128K (previously just called the Macintosh), which streamlined manufacturing. The resolution of the display was the same at 512 × 342.
Apple sold a memory upgrade for the Macintosh 128K for $995 initially, and reduced the price when 256Kb DRAM prices fell months later.[4]
The applicationsMacPaint andMacWrite were still bundled with the Mac. Soon after this model was released, several other applications became available, includingMacDraw,MacProject, MacintoshPascal and others. In particular,Microsoft Excel, which was written specifically for the Macintosh, required a minimum of 512 KB of RAM, but solidified the Macintosh as a serious business computer. Models with theenhanced ROM also supported Apple'sSwitcher, allowingcooperative multitasking among (necessarily few) applications.
TheLaserWriter printer became available shortly after the 512K's introduction, as well as the number pad, mic, tablet, keyboard, mouse, basic mouse, and much more. It utilized Apple's built-in networking schemeLocalTalk which allows sharing of devices among several users. The 512K was the oldest Macintosh capable of supporting Apple'sAppleShare built-in file sharing network, when introduced in 1987. The expanded memory in the 512K allowed it to better handle large word-processing documents and make better use of the graphical user interface and generally increased speed over the 128K model.
Color Systems Technology used an army of 512K units connected to a customIntel 80186-based machine to colorize numerous black-and-white films in the mid-1980s.[5]
The original 512K could accept Macintosh system software up to version 4.1;System Software 5 was possible if used with theHard Disk 20.
An updated version replaced the Macintosh 512K and debuted as theMacintosh 512Kenhanced in April 1986. It differed from the original 512K in that it had an800 KB floppy disk drive[6] and the same improvedROM as theMacintosh Plus. With the exception of the new model number (M0001E), they were otherwise cosmetically identical. The stock 512K could also use an 800 KB floppy disk drive as well as theHard Disk 20, the first Macintosh hard disk from Apple, attaching to the floppy disk port. The Hard Disk 20 required 512 KB RAM and when used with the Macintosh 512K which had the old 64 KB ROM, a special system file on floppy disk that loaded the improved ROM code into RAM, thus reducing the RAM available for other uses. This was not required by the 512Ke. Apple offered an upgrade kit which replaced ROMs and the floppy disk drive with an 800 KB double-sided one, essentially turning it into a 512Ke. One further OEM upgrade replaced the logic board and the rear case entirely with that of theMacintosh Plus which had a SCSI port and 1 MB RAM expandable to 4 MB.[7]
As with the original Macintosh, the 512K was designed with no slots for upgrade boards and had no hard-disk controller, so the few internal upgrades that were available for the 512K, such asGeneral Computer's US$2,795 Hyperdrive hard drive, had to plug directly into the 68000 processor socket.[8] Other such upgrades included "snap-on"SCSI cards and RAM upgrades of 2 MB or more.
| Timeline ofCompact Macintosh models |
|---|
 See also:List of Mac models andCompact Macintosh |
