Wayne Stewart wrote: > On the good side 64k offers only a very small speed difference over 32k > and a number of people have mentioned having to go to 32k for stability at > higher speeds. Refer to my earlier posting on the cache architecture: if you have an 8 MB memory expansion card installed in the IIgs, 32 KB cache will cause a speed penalty, as the memory above the 7 MB mark is not cached. The IIgs likes to place some non-relocatable data at the top of memory, but I don't know how often it is accessed and therefore whether this speed penatly will be significant. The RAM disk would also occupy this area (if you were using it). Bryan Parkoff wrote: > Please state your opinion what you think is better to do with the CP/M > and/or 6502 microprocessor. Is CP/M much like Intel CPU? That is like asking whether a 6502 or ProDOS is better. CP/M is an operating system. 6502 is a microprocessor. CP/M originally ran on the Intel 8080 processor, including derivatives like the 8085 and Zilog Z80. On the Apple II, I believe all of the CP/M implementations used a Z80. The 8080 and Z80 are both 8-bit processors with a 64K address space, similar to the 6502. There was also an Intel 8086/8088 port of CP/M, called CP/M-86. The 8088 is the original CPU used in the IBM PC. The 8086 is identical to the 8088 except that the '86 has a 16-bit data bus, while the '88 has an 8-bit data bus. The 8080 and 8086 are not binary compatible. The 8086 is much more powerful than the 8080, supporting up to 1M address space and wider range of 16-bit calculations. MS-DOS/PC-DOS 1.0 was derived by Microsoft from an operating system known as QDOS (Quick and Dirty Operating System). QDOS was originally designed as a workalike of CP/M for the 8086 processor, using almost identical system calls for file I/O operations, but with a different file system. I think it predated CP/M-86. MS-DOS 1.0 doesn't have any signficant advantages over CP/M, but version 2.0 introduced subdirectory support and a more advanced file I/O system call interface, which made it much better. -- David Empson dempson@actrix.gen.nz