On 12/07/2012 23:12, Rod Speed wrote:


"Reentrant" wrote in message
...
On 12/07/2012 16:26, Man at B&Q wrote:
On Jul 12, 8:31 am, (Steve Firth) wrote:
John Rumm wrote:
On 12/07/2012 00:50, Steve Firth wrote:
John Rumm wrote:

.....
Your apparent try to portray IBM/Lenovo as champions of choice is
making
me choke a little. That's IBM that would never, ever publish to its
consumers any worthwhile technical documentation for its systems and

That's odd as the first IBM PC I camne across (circa 1982 or '83) came
with complete schematics and documentation.

MBQ

The Technical Reference Manual didn't actually come with the PC - you
had to buy it separately. It included all the adapter dimensions, bus
pinouts, bus timings, and full BIOS documentation.

Yes.

I'm pretty sure it even had the BIOS source code.

Yes.

My job in the early days of the IBM PC Co was to help and encourage
third parties to develop adapters and add-ons which IBM didn't have
(eg network cards, 3270 emulators, high-end graphics). All the
necessary technical information was published.

Later on, PS/2 Micro Channel Architecture was also fully documented
and licenced to OEMs.

But it never was for the AT.

It was the competition - Compaq and the like - who claimed the PC and
PS/2 were proprietary.

Nope, IBM did with the PS/2. That's why it had to be licensed.

Not true, though a lot of the technology needed to make it work, such
as DMA, was patented and royalty payments due.

That's not right with DMA.

IBM has lots of PC-related DMA patents -
eg http://www.google.com/patents?id=gmobAAAAEBAJ

ie not for the concept of DMA itself, or later Bus Mastering, but for
specific ways of implementing them.

I didn't think "proprietary" and "licenced" were the same. Doesn't the
former mean the interface is not documented and competitors can't use it
- even for a fee?

--
Reentrant