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Entry Level Family Technical Overview

[Amiga] [Apollo] [Atari] [Mac II] [Mac Entry Level] [Mac Quadra] [Mac AV] [NeXT Architecture] [Radius Rocket] [Sun 3 Series]


This page documents a series of machines developed by the Entry Level devision withing Apple which includes the Macintosh LC architecture and some Macintosh Classic. The Macintosh LC was named as such with LC representing "Low Cost". The Macintosh Classics were dubbed "Classic" for the famous design of the Macintosh Plus with its built in monitors. Other Macintosh LC computers had a built in monitor as well. Unique feature of these computers is that there was a removable duaghter board that was interchangeable. You could take one duaghter board and insert it into a Macintosh Color Classic, a larger "Hook" design with a built-in monitor, or a LC desktop design. Later computers also contained various expansion ports for optimum configurability. Amazingly, the Macintosh LC630, also sold as the Macintosh Quadra 630, sold about 500,000 units in one quarter and was one of the most configurable. This computer was only a 68040 processor, but outsold the entire PowerMacintosh line at that time. The predecessor Power Macintosh 6300 did remarkably well also.

Figure 1.1 Performance of Entry Level Machines


Linux/m68k (macLinux) Notes

Generally Linux/m68k runs on any MC68020 with an external MC68551 PMMU (Paged Memory Management Unit) processor. Other processors after the MC68020 have a built-in MMU (Memory Management Unit) with exception of the MC68EC030 and other EC processors which cannot work with Linux/m68k. It is good to have an FPU (Floating Point Unit) or math co-processor as it is slow to use an emulator and difficult to configure. Commonly, MC68881 math processor is used with the MC68020 and the MC68882 is used with the MC68030. The newer MC68040 contains a built-in math coprocessor. The MC68LC040 does not have the built-in math coprocessor.

Several Macintosh LC computer can prove problematic as they contain a defective processor called the MC68RC040 which contains a faulty FPU or math coprocessor. Becuase of this situation you cannot use a software FPU emulator. Being that this is a hardware flaw, users are advised to upgrade processor to a full MC68040 processor which has a built-in FPU.

Linux/m68k has the ability to run on any Quadra computer and is currently able to boot with a look in prompt on several machines. The Centris 610 and some models of the Quadra 610 contain the 68LC040 processor which does not have a functional FPU or math coprocessor. For these machines will need a the 68LC040 will need to be replaced with a normal 68040 processor or use a software FPU emulator.

Currently the Quadra 900 and Quadra 950 does not have the needed support to get this machine to work properly. There are two IOP6502 ICs which control the floppy/serial and adb. Without public documentation, keyboard, mouse, floppy, and serial may not function.

Components (Under Construction)

The following is a list of the components that make up the capabilities of the Macintosh II Family line:


The Macintosh Classic and LC series contains the following ports:

The Macintosh Classic II series contains the following has a built-in 9" monochrome display (512x384) and contains:

The following computers contain an Serial port (RS232) with an 9 pin mini-din: Macintosh LC520, Macintosh Quadra 605 or LC475,

* This port is incompatible with the familiar RS232 PC Serial port as it does not contain the missing 9th pinout. This causes a problem for the DOS compatability card where many MIDI applications use this ninth pin. Most modem below 2.88K will work. Also note that the SCC chipset uses a different style of communication familiar in the PC clone world.


Macintosh Classic II

Macintosh Color Classic

Macintosh Color Classic II

Macintosh LC

Macintosh LC II

Macintosh LC III

Macintosh LC III+

Macintosh LC 475 (Quadra 605)

Macintosh LC 520

Macintosh LC 550

Macintosh LC 575

Macintosh LC 580

Macintosh LC 630 (Quadra 630)


Under Construction:

Other Pages of Interests

These pages were created to illustrate the basic machine information of the Macintosh II Family as a service to the MacOS and Linux/m68k community. I would deeply appreciate any suggestions people may have regarding additional information they would like to have added. Email