Re: IBM microdrive.

David Given wrote:
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> On Monday 18 February 2002 19:29, you wrote:
> [...]
> > >  Timing buffered disk reads:  64 MB in 152.29 seconds =430.34 kB/sec
> > >  Timing buffered disk reads:  64 MB in 199.30 seconds =328.83 kB/sec
> > >
> > >  Timing buffer-cache reads:   128 MB in  4.46 seconds = 28.70 MB/sec
> > >  Timing buffer-cache reads:   128 MB in  4.15 seconds = 30.84 MB/sec
> > >
> > > It's slower than 10Mb ethernet! I should have stuck to NFS! It's reported
> > > as a TOSHIBA MK5002MPL. Any suggestions on how to speed it up? I tried
> > > turning on multcount, but that didn't have any effect, as you found out.
> >
> > Ouch!  And I thought my card was a slug!  So we have a puzzle on our
> > hands.  According to hdparm -v, the only thing I have turned on is
> > readahead=8.  Does that match your setup?  Anybody else with one of
> > these drives noticing bad performance?
> 
> I tried some more benchmarks.
> 
>  Timing buffered disk reads:  64 MB in 347.34 seconds =188.68 kB/sec
>  Timing buffered disk reads:  64 MB in 340.25 seconds =192.61 kB/sec
>  Timing buffered disk reads:  64 MB in 343.53 seconds =190.77 kB/sec
> 
> I think there's actually something *wrong* here. hdparm -v says:
> 
> /dev/hda:
>  multcount    =  0 (off)
>  I/O support  =  0 (default 16-bit)
>  unmaskirq    =  0 (off)
>  using_dma    =  0 (off)
>  keepsettings =  0 (off)
>  nowerr       =  0 (off)
>  readonly     =  0 (off)
>  readahead    =  8 (on)
>  geometry     = 10390/15/63, sectors = 9818550, start = 0

I agree there's something wrong, but those are the same values
I see from hdparm -v.  Are you getting any interesting messages
in /var/log/kern.log?  This is what I see at boot time:

hda: TOSHIBA MK5002MPL, ATA DISK drive
ide0 at 0xf7000000-0xf7000007,0xf700000e on irq 32
ide_cs: hda: Vcc = 3.3, Vpp = 0.0
hda: bad special flag: 0x03
hda: 9818550 sectors (5027 MB) w/212KiB Cache, CHS=10390/15/63
Partition check:
 /dev/ide/host0/bus0/target0/lun0: p1 p2

There are no further messages from the ide driver at run time.

> [...]
> > > That's the problem. I tried a 100Mb card we had here, and the iPAQ didn't
> > > even notice I'd inserted it. The card was CardBus only. I'd rather not
> > > order one and find out later that it didn't work.
> >
> > Was the card you tried listed in the compatibility list?  If so, some
> > feedback to whoever maintains the list might be in order.
> 
> No, it was just one we had lying around that I tried on the off-chance.
> Actually it seems that the maximum throughput on the PCMCIA bus wouldn't make
> it worthwhile. (Although your hdparm readings seem to indicate a higher
> transfer rate than our calculations suggest is possible, so it could well be
> we've miscalculated.)

Our local PC guru says he tried a 100Mb card in his iPAQ under CE and
got
only a slight improvement over 10Mb.  He chalked it up to either the
PCMCIA bus
lacking throughput, the CPU just being too slow, or both.  He thinks the
iPAQ
has an old-style PCMCIA bus, not the newer Cardbus design.

> Not being able to swap is a real pain, and renders the device pretty unusable
> for our purposes. Is it possible to use a stock kernel on the iPAQ? I'd like
> to standardise on 2.4.17, which is what we use on all the other Linux
> platforms we deal with. I'm not terribly happy about using heavily patched
> kernels.

Dunno.  Perhaps one of the Intimate developers could comment?  It's
been years since I felt much need to mess with a kernel, much less
one on an experimental contraption like an iPAQ.  :-)

Paul Allen
-- 
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