On Sunday 14 January 2001 16:32, you wrote:
> Addressed to Civileme:
> Once I looked at what you posted in your article, re-read some of the
> hdparm info page, and did some experimentation I became somewhat confused.
>
> Here is the except out of the info page:
>
>
> -i Display the identification info that was obtained
> from the drive at boot time, if available. This is
> a feature of modern IDE drives, and may not be sup
> ported by older devices. The data returned may or
> may not be current, depending on activity since
> booting the system. However, the current multiple
> sector mode count is always shown. For a more
> detailed interpretation of the identification info,
> refer to AT Attachment Interface for Disk Drives
> (ANSI ASC X3T9.2 working draft, revision 4a, April
> 19/93).
>
> Version 3.9 February 2000 2
>
> HDPARM(8) HDPARM(8)
>
> -I Request identification info directly from the
> drive, which is displayed in its raw form with no
> endian changes or corrections. Otherwise similar
> to the -i option.
>
> When I ran through both options I got this:
> [root@tick /root]# hdparm -i /dev/hdg
>
> /dev/hdg:
>
> Model=IBM-DTLA-307045, FwRev=TX6OA50C, SerialNo=YMDYMM67566
> Config={ HardSect NotMFM HdSw>15uSec Fixed DTR>10Mbs }
> RawCHS=16383/16/63, TrkSize=0, SectSize=0, ECCbytes=40
> BuffType=DualPortCache, BuffSize=1916kB, MaxMultSect=16, MultSect=16
> CurCHS=16383/16/63, CurSects=16514064, LBA=yes, LBAsects=90069840
> IORDY=on/off, tPIO={min:240,w/IORDY:120}, tDMA={min:120,rec:120}
> PIO modes: pio0 pio1 pio2 pio3 pio4
> DMA modes: mdma0 mdma1 mdma2 udma0 udma1 udma2 udma3 udma4 *udma5
> [root@tick /root]# hdparm -I /dev/hdg
That's a udma 100 setting
>
> /dev/hdg:
>
> Model=TDAL3-7040 5 o?, FwRev=5AC0BI-M, SerialNo=
> Y DMMY6M5766b
> Config={ NotMFM Fixed Removeable DTR<=5Mbs DTR>5Mbs DTR>10Mbs dStbOff
> TrkOff } RawCHS=16/0/0, TrkSize=63, SectSize=0, ECCbytes=13903
> BuffType=40, BuffSize=10796kB, MaxMultSect=0
> (maybe): CurCHS=63/64528/251, CurSects=1531969808, LBA=yes,
> LBAsects=458752 IORDY=no
> PIO modes: pio0
> DMA modes:
>
> My understanding is that the -i option is showing what the kernel sees at
> boot time when it auto configures the drive. When I have the auto
> configure option set for /dev/hde and /dev/hdg, the system hangs on
> /dev/hdg with a Promise Utra100 controller. Tracing this further, after
> boot I typed in 'hdparm -u1 -c1 /dev/hde; hdparm -u1 -c1 -d1 /dev/hdg'.
> This seemed to execute, but when I typed in 'hdparm -t /dev/hdg' the system
> complained about a DMA time-out and hung. (Console did not respond to
> anything.) When I hit the reset switch and brought the system back up I
> did the following. At the prompt I typed in 'hdparm -u1 -c1 /dev/hde;
> hdparm -u1 -c1 -d1 -X69 /dev/hdg'. (Note the -X 69 option). When I typed
> in 'hdparm -t /dev/hdg' I got:
>
> [root@tick /root]# hdparm -t /dev/hdg
>
> /dev/hdg:
> Timing buffered disk reads: 64 MB in 1.79 seconds = 35.75 MB/sec
>
> Now if the highest defined rate so far in the IDE world is UDMA mode 5 and
> the kernel seems to detect that that is the highest mode available and the
> controller supports UDMA mode 5, then how can your why be true? ("Some Hard
> disk drives advertise to the software that they are capable of higher data
> rates than they actually can do.")
Crappy drives outside of specs--sorry but it even happens with IBM despite
their care. Thus the drive advertises to the software that it can run
udma100 and the kernel tunes to that and times out because the tolerances of
the kernel are tighter than the drive. Mostly this is restricted to a few
brands, and works better with the running kernel than the install kernel.
And just because it reads OK on one speed test does not mean the drive is
running reliably. I wish there were better explanations, but we seem to be
more in the area of plumbing than of science here.
Also, most people do not check or develop a REGULAR schedule of cable
rotation (Put in new and throw away old) There's vibration and we are
counting on cheap plastic to maintain tight connections of metal to metal in
the insulation displacement configuration.
Naturally, in those short articles, I am asked to condense the full
explanations greatly, most users don't want to be bothered with that much
detail. Here you will find a much more thorough explanation:
http://www.mandrakeforum.com/article.php3?sid=20001213074438
As to why this works with Windows but not with Mandrake--remember windows has
no native ATA/100 drivers--They are by the interface
manufacturers and are far less efficient (read sloppier and more out of spec
tolerant) than those prepared by Andre Hedrick and other kernel hackers.
Civileme
