a friend wants to buy a laptop to run BSDI...

[Keith Moore <moore@CS.UTK.EDU>]

A friend of mine wants to buy a new laptop to run BSDI.  I run NetBSD
on my TP750, but it's been a real pain to work around all of the
incompatibilities (I'm currently pulling my hair out trying to get
NetBSD 1.0 to run).  Are the newer models any better, and if so, how?

Here's my reply to a message he sent me.  If anyone has additional
information that seems apropos, I'll forward it to him.  In
particular, I'd like to hear from anyone else who is running *BSD on a
thinkpad.

Thanks,

Keith

------------------------------------------------------------------------------
(my reply)

> 
> Thinking of a laptop upgrade.  As you know, I am a BSDI user.  Some
> questions.
> 
> Of what compatibility issues should I be aware?  What models should I avoid?

The later thinkpad models have fewer compatibility problems, but here's
what I've run into:

+ 2.88 Mb floppy drives/controllers are not widely supported.  Even though
  the hardware is usually software compatible with 1.44 Mb hardware, the
  bios will report a different value.  The newer thinkpads have 1.44 Mb
  drives so this is not a problem for them.

+ floppy disk change line in a ThinkPad has the opposite assertion level 
  from AT-bus machine.  May not be a problem for BSDI (NetBSD doesn't
  care); but this was a problem for Linux.

+ keyboard controller on my TP750 emulates a very picky PS/2 keyboard.
  It acts like an AT keyboard after booting, but if the BSDI device driver
  resets the keyboard, it might not be able to deal with the scan codes
  that result.  Also things like the power switch and some of the special
  functions don't seem to work after resetting the keyboard
  controller.  YMMV.

+ mouse controller (trackpoint) has similar problems.  It mostly acts like 
  a PS/2 mouse -- but is not recognized as one when the device driver 
  tries to probe it.

+ sound chip on older models isn't compatible with much of anything.
  newer models emulate a soundblaster in hardware.

+ XFree86 3.x works on my monochrome model, though it doesn't quite handle
  the 90c24 chip right in all modes.  It seems to work fine if you
  treat the display as a 256 color SVGA.  XFree86 2.x works fine, but
  may not support graphics acceleration.

+ There's a wierd bug on the TP750 where it wants to use the top 4K
  of conventional memory for the BIOS.  If the OS stomps on it,
  the system will just get wedged.  (One symptom was that an attempt
  to use a parallel printer caused the system to cold boot.) I'm not 
  sure if this "feature" still exists on later machines.

My best guess is that you'll need to do some kernel tweaking to
get things running smoothly.  Again, maybe the later models work
better, but I'd ask BSDI about it if I were you.


As for models to look for / avoid:

+ In general, the 360 and 75x series are pretty nice.  The 701
  (butterfly) is supposed to be nice also, but I haven't seen one.
  I don't like their subnotebooks.  My dad has a 501.  It works
  okay but I can't stand typing on its keyboard.  If you want
  a subnotebook, a Compaq Aero is nicer.

+ make sure you can get a dual-voltage charger and extra batteries.
  some of the recent models come with only a single-voltage brick
  (which is smaller and lighter but probably not what you need).
  also, some models use different batteries than others, and not 
  all of them have spares or external chargers available yet.  (ask 
  John Klensin about his)

+ IBM has a gazillion different laptop displays.  I think they
  paniced when the things were in short supply, and rather than
  try to get enough of any one display type to satisfy the demand,
  they just bought displays from everybody.  I still prefer monochrome
  because it gives a lighter machine and better battery life,
  but all of the color ones have better contrast (given a reasonable
  choice of foreground/background colors) than a mono LCD.

+ Disks come in sizes from 170 Mb (just discontinued?) to over
  a Gb.  If you want to upgrade later you can replace it with
  a 2.5" 17mm high drive, but you have to open up the little
  disk carrier and break warning seals etc.  Or you can buy a
  thinkpad-ready disk complete with its own carrier -- but they're
  fairly expensive compared with bare drives.  I have a 340 Mb
  drive which means I'm always trying to find something to delete.
  For a new system, I'd get the 810 Mb drive at least.
 
> How do BSD and power management interact?  What's the result on battery
> life?

+ My guess is that there's no support for APM in BSD.  Some of the power
  management is done in hardware, and this will probably still work.
  But it won't turn off your devices when you're not using them --
  so your battery life won't be as good as under windows.  I get 
  around 3 hours per battery doing things like editing.  NiMH don't
  have the same memory problems as NiCd batteries, but it still helps 
  to do full charge-discharge cycles.
 
> The TFT display seems small.  Will I like the STN better?

Yes, but any color display you get will be better than what you have now.
 
> Can I leave it on for weeks on end?

Yes.  I keep my TP plugged in the docking station at home when  I'm
not on the road.
 
> Connection for external monitor?

works fine for me.  On my machine, the video controller generates 
different clocks depending on whether the external monitor is
enabled.  There's a key on the keyboard that toggles between one
and the other.
 
> Where does one get good pricing and selection?

sorry, can't help you here.  IBM does have a place to mail order 
discontinued models at reasonable prices, if you're interested in 
that I can find it.

I'll forward your question to the tp750 mailing list to see what
other advice they might have.

Keith