Macintosh 512K
The Macintosh 512K is a personal computer that was designed, manufactured and sold by Apple Computer from September 1984 to April 1986. It is the first update to the original Macintosh 128K. It was virtually identical to the previous Macintosh, differing primarily in the amount of built-in random-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.[2]
Not to be confused with Macintosh 512Ke.Also known as
M0001W
September 10, 1984
US$2,795 (equivalent to $8,200 in 2023)
April 14, 1986
Motorola 68000 @ 7.8338 MHz (Effectively 6 MHz)
512 KB RAM (built-in)
9 in (23 cm) monochrome, 512 × 342
The Mac 512K originally shipped with Macintosh System 1.1 but was able to run all versions of Mac OS up to System 4.1. It was replaced by the Macintosh 512Ke and the Macintosh Plus. All support for the Mac 512K was discontinued on September 1, 1998.
Features[edit]
Processor and memory[edit]
Like the Macintosh 128K before it, the 512K contained a Motorola 68000 connected to 512 KB of DRAM by a 16-bit data bus. Though the memory had been quadrupled, it could not be upgraded. The large increase earned it the nickname Fat Mac. A 64 KB ROM chip boosts the effective memory to 576 KB, but this is offset by the display's 22 KB framebuffer, which is shared with the DMA 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 256 Kb DRAM prices fell months later.[3]
Software[edit]
The applications MacPaint and MacWrite were still bundled with the Mac. Soon after this model was released, several other applications became available, including MacDraw, MacProject, Macintosh Pascal 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 the enhanced ROM also supported Apple's Switcher, allowing cooperative multitasking among (necessarily few) applications.
New uses[edit]
The LaserWriter 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 scheme LocalTalk which allows sharing of devices among several users. The 512K was the oldest Macintosh capable of supporting Apple's AppleShare 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 custom Intel 80186-based machine to colorize numerous black-and-white films in the mid-1980s.[4]
System software[edit]
The original 512K could accept Macintosh system software up to version 4.1; System Software 5 was possible if used with the Hard Disk 20.