[ILUG] Re: [slightly OT] IDE Speed on 486? - SOLVED (partly...)

[Thomas Ribbrock]

Thanks to all who replied - learned a few new bits!

In any case: I managed to improve the drive speed from 1.4MB/s to 2.1MB/s by
doing the following three steps:

1) The VLB controller actually uses a PDC20230-C chip from Promise. Promise
   doesn't have any datasheet on it, but they sold a VLB card using this
   very chip, so by crossreferencing I found two jumpers on my card labled
   "Speed". The settings were "Speed 0", "Speed 2", "Speed 4" and "Speed 6".
   The jumpers were not present, instead wires were soldered into the "0"
   setting. I replaced those by jumpers and tried the "Speed 6" setting.
   That helped a good bit. (magic smoke will curl out of that box any minute
   now... ;-) )
2) hdparm -c1 /dev/hda
   to enable 32bit access - gave another few bytes/s
3) hdparm -m2 /dev/hda
   enable block mode with 2 sectors (4 or 8 was worse) and another few
   bytes/s.

The time to flush during mail download is significantly shorter and
approaches what I had on the P133. Overall, the performance of that box is
now definitely up to the task and it seems to be stable. Once I managed to
add a voltage regulator, I'll try a DX4/100 CPU... :-)

Cheerio,

Thomas
-- 
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      Thomas Ribbrock    http://www.bigfoot.com/~kaytan    ICQ#: 15839919
   "You have to live on the edge of reality - to make your dreams come true!"