[rescue] Re: SPARC memory query

[Joshua D Boyd]

On Thu, Nov 28, 2002 at 05:48:17PM -0500, Sheldon T. Hall wrote:
> "Gavin Hubbard" <ghub005 at xtra.co.nz> wrote ...
> 
> PC hardware design continuity isn't all that great, really.
> 
> Busses:    ISA -> EISA -> VESA -> PCI (with an MCA sidecar and AGP, too)
> Video:     MGA -> CGA -> EGA -> VGA -> SVGA (plus PGA and XGA)
> Memory:    30-pin -> 72-pin -> 168/66 -> 168/133 -> Ghod knows
> (parity/non-parity, FPM/EDO, ECC)
> Disks:     MFM -> pre-IDE -> IDE -> EIDE -> ATA/166 (plus SCSI in all its
> variations)
> Floppies:  5.25/160 -> 5.25/180 -> 5.25/360 -> 3.5/1400 (plus 3.5/1700,
> etc.)
> CPU:       Too many dam' "sockets" to keep track of.
> 
> They even changed the fscking serial port connectors, mouse connections, and
> keyboard connections at one time or another.

> What makes a PC a PC is that it's cheap and conforms to the PC "standards"
> of the day.  Unfortunately, those "standards" have generally been determined
> by cost rather than utility, and with little view of the future.  They
> change frequently, too.

I wouldn't really say they change that much.  I mean, it's only been the
past year or so that one would have trouble buying a new machine with
ISA.  And further, wouldn't plain DOS still boot on most new machines?
It seems to me that the standards here are that programs don't really
need to know much about PCI to be able to use a PCI graphics card when
it had previously been able to use an ISA one.

A P3 with a VESA biosed and VGA compatible video (a lot of the cards out
there in other words) will still run vast amounts of old software, from
at least the 286 days, if not the earliest days.  This happens because
the BIOS masks that you have PS2 or USB keyboards, and most video cards
are still VGA compatible, and hence mostly EGA and CGA compatible (both
EGA and CGA had rarely used special features that aren't nescessarily in
VGA). 

I don't know.  I just seems to me that the real standard is that one can
count on VGA, or the subset of MCA, CGA, and EGA that VGA supports, and
one can count on the BIOS, and that really all of these things might be
flakey since they arent exactly real standards.

-- 
Joshua D. Boyd