I've been making notes for an article on used laptops for a while but
one issue that is appropriate for immediate comment is the problem of a
"Web capable" laptop. Every time I talk about downloads the issue
comes up. Why am I only using 9600 bps when I have a 28.8Kbps or faster
MODEMs? The problem is that until late in the Intel 486 period laptops
only used the older 8250 UARTs. So if you are using an external MODEM
on one of those machines, with a buss speed of under 33MHz, 9600 bps is
about as fast as you can go without data over-flows where the MODEM has
to send a flow control back to the source. While you can survive the
flow control handling on some BBSes and private networks, I have found
that it doesn't tend to work on ISP's. It's possible that on a really
good ISP I could sit down with a technician and figure out a workable
setup, but not on this one.
[1999/02/15]
On my laptop, in theory I can get around this by using a PCMCIA card MODEM. But that's something I haven't gotten around to trying. I could have bought one by now, but with all the wiring I currently have running around my computers, I would rather just use one MODEM for both my "main computers". Those are my desktop Mac and my Windows laptop. So that means my best solution was to use my single external modem through a switching box for my RS-232 cables. The switch selects which computer can access the MODEM.
A lot of people use external MODEMs for their laptops for the same reason -- to share between multiple computers, or simply because they can get them cheaper than PCMCIA MODEMs. This is particularly relevant if you're specifically planning on buying an inexpensive used computer as a second computer for occasional use.
If you are looking at the used computers in the first place it's
probably because of their lower prices. And so you will want
to know which computers have which UART. Unfortunately, there's no
easy way to tell which of the "older" computers have older 8520 UARTs
and which have the newer 16550 UARTs. All I can give you is the
generalization that the major computers changed from around 1994 to
1995 and in general cheaper computers changed later than the more
expensive models. Beyond that you'll have to ask people or look up
the specification. "Someday" I'd like to compile a list of the
transition models of various brands but I haven't done it yet. But if
you want a really practical "Web laptop" with a reasonable future,
but at "used" prices, you're going to have to decide early in the
process whether you can tolerate a slow RS-232 port and look into
this problem.
[1997/02/28]
On July 9, 1997, at COMDEX I found Gainbery Computer Products Inc.,
advertising thei CPU Maximizer line of upgrade for 486 computers
to "GB586" processors. Included was a version for 486 technology
laptop computers. Their phone number is (905) 415-0480.
http://www.gainbery.com/
[1997/09/02]
Aug. 12, 1997, Computer Reseller News reports on Computer Horizon's
Year 2000 program. Within that report is an interesting quote.
According to that report, "Steven Morgenthal, president of Computer
Horizons' enterprise management division said PCs and network
components that contain Intel 386 or earlier processors 'will not
only have a problem with the millenium date change, but will
calculate the leap year incorrectly -- thus causing a ripple
effect in all date calculations." I don't know how this can be
a "hardware" specific problem for 386 devices and earlier. Isn't
it s a software problem?
[1997/08/15]