Very Computer

I have four hard disks (IDE) which were not running with DMA turned on (i.e., they were all running in "default 16-bit").  For purposes of this post, they are:

HD1 = Maxtor 2GB
HD2 = Maxtor 4GB
HD3 = Maxtor 55GB
HD4 = Maxtor 10GB

(I don;' really have a fondness for Maxtor; three of the drives were in computers I bought, but I did buy the 55GB one).

Anyway, I ran 'hdparm -t' on each, the the results were:

HD1: ~2.5 MB/sec
HD2: ~3.5 MB/sec
HD3: ~1.75 MB/sec
HD4: ~28.0 MB/sec (yes, I was surprised at this as well; I ran it three times, just to make sure!

After running 'hdparm -c 1 -d 1' on each, the results of 'hdparm -t' are now:

HD1: ~7.5 MB/sec
HD2: ~14.5 MB/sec
HD3: ~2.25 MB/sec
HD4: ~28.0 MB/sec (I didn't really expect it to change very much)

My biggest disappointment was with HD3 (the 55GB), particularly since I had bought it specifically for use in a "digital VCR" application.  As the subject of this post suggests:

  1. Are there any factors that I am able to control (beyond turining DMA on, which I've already done) to increase throughput on HD3 (I'd even be happy with ~5MB/sec throughput).

If there is any further information you would need from me to make this determination, please let me know, and I will do my best to get it for you.

TIA,

: I have four hard disks (IDE) which were not running with DMA turned on (i.e., they were all running in "default 16-bit").  For purposes of this post, they are:

: HD1 = Maxtor 2GB
: HD2 = Maxtor 4GB
: HD3 = Maxtor 55GB
: HD4 = Maxtor 10GB

: (I don;' really have a fondness for Maxtor; three of the drives were in computers I bought, but I did buy the 55GB one).

: Anyway, I ran 'hdparm -t' on each, the the results were:

: HD1: ~2.5 MB/sec
: HD2: ~3.5 MB/sec
: HD3: ~1.75 MB/sec
: HD4: ~28.0 MB/sec (yes, I was surprised at this as well; I ran it three times, just to make sure!

: After running 'hdparm -c 1 -d 1' on each, the results of 'hdparm -t' are now:

: HD1: ~7.5 MB/sec
: HD2: ~14.5 MB/sec
: HD3: ~2.25 MB/sec
: HD4: ~28.0 MB/sec (I didn't really expect it to change very much)

: My biggest disappointment was with HD3 (the 55GB), particularly since I had bought it specifically for use in a "digital VCR" application.  As the subject of this post suggests:

:   1. Are there any factors that I am able to control (beyond turining DMA on, which I've already done) to increase throughput on HD3 (I'd even be happy with ~5MB/sec throughput).

: If there is any further information you would need from me to make this determination, please let me know, and I will do my best to get it for you.

Have you checked BIOS settings? Linux will happily work with a drive that
is NOT recognized by BIOS, but then you will get bad performance.
Most IDE controllers (all?) are not fully supported by Linux, namely
BIOS must first initialize the controller, and then Linux can use
its full capabilities. If BIOS do not initialize a chanell (drive)
then the drive will still work, but you will get performace in range
of 2-3MB/sec. On modern drive anything below 20MB/sec is slow.

So, check if BIOS sees the drive and activate the best mode in BIOS.
On one computer I had to upgrade the BIOS -- after upgrade BIOS
initialized the controller and performace went up from 3MB/sec to
20MB/s.

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                              Waldek Hebisch