[FreeBSD Questions] Filesystem image as root

James Phillips anti_spam256 at yahoo.ca
Mon Nov 16 08:55:25 UTC 2009

--- On Sun, 11/15/09, CyberLeo Kitsana <cyberleo at cyberleo.net> wrote:
> James Phillips wrote:
> >> Date: Sat, 14 Nov 2009 20:29:59 -0600
> >> From: CyberLeo Kitsana <cyberleo at cyberleo.net>
> >> Subject: [FreeBSD Questions] Filesystem image as
> root
> >>
> >> The single IDE connector is accessible via the
> legacy ISA
> >> ports, and is
> >> thus limited to PIO modes (about 1.6MB/sec max,
> even with
> >> an actual hard
> >> drive instead of a CF card).
> > 
> > You are off by an order of magnitude (base 2 or 10):
> > Pio mode 0 is ~3.3 MB/s
> > Pio mode 4 is ~16.7 MB/s
> > 
> > http://www.pcguide.com/ref/hdd/if/ide/modesPIO-c.html
> > 
> > You can probably set PIO mode 4 for with:
> > # atacontrol mode ad0 PIO4
> If only that were true in this case.
> (85eef1f3)[root at ss4200 ~]# atacontrol mode ad0 PIO4
> current mode = PIO2
> (85eef1f3)[root at ss4200 ~]# atacontrol mode ad0 PIO4
> current mode = PIO2
> (85eef1f3)[root at ss4200 ~]# dd if=/dev/ad0 of=/dev/null
> bs=4096 count=4096
> 4096+0 records in
> 4096+0 records out
> 16777216 bytes transferred in 10.111748 secs (1659181
> bytes/sec)
> Nothing I've tried seems to boost the throughput, hence the
> desire to
> use a compressed cached filesystem image.
> Thanks for the suggestions, though!

I thought the laptop I was "fixing" last week was bad: running Vista with a 10MB/s transfer rate :P

The drive in my Pentium 166 gets 11-12MB/s.

I actually looked up both the PIO modes:

And the spec sheet (assuming Tom's hardware was wrong) before composing my original reply:
Intel® Entry Storage System SS4200-E
Technical product specification [PDF]

I noted that the ATA port is not listed as a feature, which is not a good sign. It does appear in the block-diagram labeled:DOM
Glossary definition: Disk On Module

If I had to guess: Intel did something "weird" or "non-standard" to the port, so the standard BSD driver does not work properly.
Have you read the ata(4) manual page?
The following  /boot/device.hints are suggested for ISA:
. . . port '1' probably not needed
I had a thought: it could just as easily be "pc98" if they don't intend for you to touch the "firmware."

The firmware has source code available under a GPL license.
Ver:1.0	Date:9/24/2009	Size:125585 (KB)

Ver:1.1	Date:9/24/2009	Size:244406 (KB)

If you are worried about license contamination, you may have to get somebody to look through that and document any changes (to the ATA interface). Hopefully it is based on a well-know code-base like Linux and the "diff" utility can be used.

Of course, the term "components" implies they only expose a HAL of some kind.


James Phillips

PS:"# atacontrol mode ad0" will simply print out the current mode.

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