I have an annoying problem with my computer where, if I suddenly
get to be disk-bound (be that due to intense pageing, or because
I decide to run something extraordinarilly large--like emacs) my
mouse scuttles all over the screen. This scuttling isn't random,
and if I leave the mouse still during the disk thrashing nothing
happens. If I move the mouse in the X direction, it'll skip some
50 pixels to the left (in X, on the CLI that'll be `some 6 chars
to the left'); or down if moved in the Y direction. I get a fast
multi-hop skip-dance game which I usually en up in loosing (down
at the bottom-left-hand corner).
This is an IDE disk on a unknown ISA controller (it's an old ide
+floppy+serial noname cards for which I have _no_ documentation,
is there any way to tell what the unobvious jumpers are for?). I
haven't written it off as a hardware bug yet because WfW311 does
_not_ do the cursor dance (possibly because I have yet to see it
get as disk-bound in DOS/WfW as I do in Linux. Even a light load
can trip it at times, though).
Can't really go test if it's the controller by replacing it with
another one as the only other one I have has no serial ports, so
obviously the mouse won't skip much (not being connected :).
This is kernel 2.2.3, but I've been seing it since about 2.0.36,
and 2.1.126 through 2.1.131-ac99, and all the 2.2.0 saga so far.
Only came across it recently, as it isn't all that noticeable if
you don't hit the box as hard as I've been doing lately.
It is very annoying to come across this feature, for example, on
trying to resize a window in X; the disk activity caused by your
click-n-drag is enough to start the skittle and it can be pretty
much impossible to get the window exactly as you wanted it (this
is when you're low on memory or the window's opaque).
The computer is a 386 with 20MB of RAM, no FPU (yet).
Anything else that you think might be relevant? The results from
hdparm -i aren't much use, as this seems to be more a controller
issue, but anyway
gaga:/home/john# hdparm -itT /dev/hda /dev/hdb
/dev/hda:
Model=QUANTUM FIREBALL540A, FwRev=A1M.0900, SerialNo=64552403
Config={ HardSect NotMFM HdSw>15uSec Fixed DTR>10Mbs }
RawCHS=1056/16/63, TrkSize=32256, SectSize=512, ECCbytes=4
BuffType=3(DualPortCache), BuffSize=83kB, MaxMultSect=8, MultSect=8
DblWordIO=no, maxPIO=2(fast), DMA=yes, maxDMA=2(fast)
CurCHS=527/32/63, CurSects=1064448, LBA=yes, LBAsects=1064448
tDMA={min:120,rec:333}, DMA modes: sword0 sword1 *sword2 mword0 mword1
*mword2
IORDY=on/off, tPIO={min:333,w/IORDY:120}, PIO modes: mode3 mode4
Timing buffer-cache reads: 64 MB in 27.82 seconds = 2.30 MB/sec
Timing buffered disk reads: 32 MB in 46.59 seconds = 0.69 MB/sec
/dev/hdb:
Model=QUANTUM FIREBALL1080A, FwRev=A1M.0800, SerialNo=34151752
Config={ HardSect NotMFM HdSw>15uSec Fixed DTR>10Mbs }
RawCHS=2112/16/63, TrkSize=32256, SectSize=512, ECCbytes=4
BuffType=3(DualPortCache), BuffSize=83kB, MaxMultSect=8, MultSect=8
DblWordIO=no, maxPIO=2(fast), DMA=yes, maxDMA=2(fast)
CurCHS=2112/16/63, CurSects=2128896, LBA=yes, LBAsects=2128896
tDMA={min:120,rec:333}, DMA modes: sword0 sword1 *sword2 mword0 mword1
*mword2
IORDY=on/off, tPIO={min:333,w/IORDY:120}, PIO modes: mode3 mode4
Timing buffer-cache reads: 64 MB in 27.99 seconds = 2.29 MB/sec
Timing buffered disk reads: 32 MB in 48.02 seconds = 0.67 MB/sec
Cheers,
John
--
Penguins eat apples, piss out windows, and pull faces at the Sun.
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