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Date:      Tue, 4 Jan 2000 17:03:04 -0500 (EST)
From:      Adam <bsdx@looksharp.net>
To:        Matthew Jacob <mjacob@feral.com>
Cc:        scsi@FreeBSD.ORG
Subject:   Re: sym troubles
Message-ID:  <Pine.BSF.4.21.0001041655140.7228-100000@turtle.looksharp.net>
In-Reply-To: <Pine.BSF.4.10.10001032109260.3360-100000@beppo.feral.com>

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sapphire:/dev % cp /usr/src/etc/MAKEDEV .
sapphire:/dev % ./MAKEDEV cd2
sapphire:/dev % ls -l cd*
crw-r-----  1 root  operator   15,   0 Jan  4 16:54 cd0a
crw-r-----  1 root  operator   15,   2 Jan  4 16:54 cd0c
crw-r-----  1 root  operator   15,   8 Jan  4 16:54 cd1a
crw-r-----  1 root  operator   15,  10 Jan  4 16:54 cd1c
sapphire:/dev % ls -l rcd*
crw-r-----  1 root  operator   15,   0 Jan  4 16:54 rcd0a
crw-r-----  1 root  operator   15,   2 Jan  4 16:54 rcd0c
crw-r-----  1 root  operator   15,   8 Jan  4 16:54 rcd1a
crw-r-----  1 root  operator   15,  10 Jan  4 16:54 rcd1c
sapphire:/dev % cd /root
sapphire:/root % ./stuff /dev/rcd1c 2k 0 1000
I/O returned -1, err is Operation not supported by device
sapphire:/root % ./stuff /dev/cd1c 2k 0 1000
I/O returned -1, err is Operation not supported by device
sapphire:/root % dd if=/dev/rcd1c of=/dev/null bs=2048 count=2000
2000+0 records in
2000+0 records out
4096000 bytes transferred in 1.632706 secs (2508719 bytes/sec)

dd'ing small counts doesnt seem to hint that it is caching any.  Plextor's
website thinks it has cache though, but dd causes the disk access light to
light up each time as well as spinning up / keeping the disk spun up. 

On Mon, 3 Jan 2000, Matthew Jacob wrote:

>Not if the xfer size is small enough such that it's held in the drive's
>buffer, in which case the bus speed should show up.
>
>
>> >semuta.feral.com > root rdsame /dev/rwd0c 2k 0 1000
>> >Read 2048000 bytes in 0.866316 seconds, 2308.63KB/sec in 2048 byte blocks
>> >semuta.feral.com > root rdsame /dev/rwd0c 1k 0 10  
>> >Read 10240 bytes in 0.6581 seconds, 1519.53KB/sec in 1024 byte blocks



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