Re: The Apple ][ was cool!

[Leonard Erickson <shadow@krypton.rain.com>]

Roy Miller wrote:
> 
> william strutts wrote:
> 
> > EMM memory was developed because the
> > 8088/8086 used a 20 bit address bus that limited the memory to 1 meg.
> 
> No. EMM only works with the 80206 or higher CPUs.

Very much incorrect. The EMM *driver* requirtes a *386* or better. The
LIM/EMS standard required special hardware which EMM *emulates* on a
386.

I have an old XT in the other room that has a 2 meg Intel Aboveboard in
it. It supported LIM/EMS. And with the EMM driver for that board and a
copy of QRAM (the XT equivalent of QEMM) I was able to create UMBs, load
drivers into upper memory, etc.

And because the XT *doesn't* require reserving the E000 page the way the
AT does, I was able to get 64k more upper memory than with the AT I
later had the board it. 

In fact, between QRAM and 4dos, I had more than 630k of lower memory to
load applications in. All my drivers, TSRs, etc as well as the
non-transient portion of 4dos loaded into upper memory. And I had an 80k
EMS sawp space and a 1 meg RAM disk. 
Since the system was also running at 10 MHz, and using a V20, it was
quite an "XT". 

> > Considering that the architecture of the PC was based on the 8-bit
> > processor with a 20 bit address path, it was logical that IBM would
> > utilize an OS that had was limited to that much memory.
> 
> Huh? The 8088 was a 16 bit CPU, with an 8 bit data bus, and a 20 bit address
> bus.

Until IBM redefined the term in their publicity, having an 8-bit data
bus made the 8088 an 8-bit cpu. Really. You'll find articles in the
computer magazines at the time raking IBM over the coals for lying about
it. 

The 8086 was a true 16-bit cpu by the old definition. The 8088 got used
instead because 8-bit parts were cheaper. Which made the motherboard
cheaper as they only needed 8-bit buffers and the like.

> The 8086 is a 16 bit CPU with a 16 bit data bus, and a 20 bit address bus.
> Neither was an 8 bit CPU. An 8 bit CPUs have (normally) 16 bit address lines.

See above. 
 
> 1986. And for word processing, or for spreadsheet work, the PC was faster. Why?
> It didn't have to spend so many clock cycles supporting a graphical display. It
> spent it's time doing work

Yeah, it's instructive to compare a text only display and a graphical
one. The old HGC+ screamed in Worperfect *and* supported more text mode
fonts than VGA does even now.

> Some Wintels still have an ISA or two - usually for modems. But I agree, the
> ISA 8 and 16 bit is about as dead as EISA. Though not as dead as Micro-channel!

I'm still using some microchannel and EISA systems. They work just fine
for what they are doing, and the hardware was paid for a long time ago.

BTW, you forgot VLB. <g>
 
-- 
Leonard Erickson (aka shadow{G})
 shadow@krypton.rain.com	<--preferred
leonard@qiclab.scn.rain.com	<--last resort