On 06/11/12 19:25, Jens A. Griepentrog wrote:
Dear Mailing Listeners,
Let me know, please, whether it makes sense to modify disk geometry
for solid state disks?
no
Which meaning have the default values of cylinders,
heads, and sectors for these devices?
roughly the exact same thing it has meant for IDE, SATA, and SCSI disks
since..well...about 20 years or so...not a thing.
All modern drives, and really anything made in probably the last 20
years (i.e., anything worth putting on an OpenBSD machine) use
translation...the "geometry" and "reality" are unrelated in any
recognizable way.
As an example, here are my sd1 data:
# fdisk sd1
Disk: sd1 geometry: 7783/255/63 [125045424 Sectors]
Offset: 0 Signature: 0xAA55
Starting Ending LBA Info:
#: id C H S - C H S [ start: size ]
-------------------------------------------------------------------------------
0: 00 0 0 0 - 0 0 0 [ 0: 0 ] unused
1: 00 0 0 0 - 0 0 0 [ 0: 0 ] unused
2: 00 0 0 0 - 0 0 0 [ 0: 0 ] unused
*3: A6 0 1 2 - 7782 254 63 [ 64: 125033831 ] OpenBSD
Are there any disktab entries available more suitable for usual models
of solid state disks? At least it seemed reasonable to me to take multiples
of 64 blocks for the partition sizes and offsets:
which, you will notice, is what OpenBSD does now.
If you knew what physical block size your SSD worked with, you might --
MIGHT -- see some benefit using that, but the 4k offsets seem to work
just fine. I doubt you would feel any difference...
# disklabel sd1
# /dev/rsd1c:
type: SCSI
disk: SCSI disk
label: SSDSA2SH064G1GC
duid: 78faa8282eb6f8fa
flags:
bytes/sector: 512
sectors/track: 63
tracks/cylinder: 255
sectors/cylinder: 16065
cylinders: 7783
total sectors: 125045424
boundstart: 64
boundend: 125033895
drivedata: 0
16 partitions:
# size offset fstype [fsize bsize cpg]
a: 2097152 64 4.2BSD 2048 16384 1 # /
b: 33554432 2097216 swap # none
c: 125045424 0 unused
d: 67108864 35651648 4.2BSD 2048 16384 1 # /home
To make things complete, here is the dmesg output after upgrading to 5.1.
Many thanks to the OpenBSD developers to keep the ball in play! Radeon
version xf86-video-ati-6.14.3 on ATI FirePro 2270 is a big progress;
it gives me a brillant digital image! Sometimes there are blackscreens
after switching back from X11 to console, which can be resolved by rebooting
the machine over network. Package qcad is missing but can be compiled easily
from the ports collection.
Best regards,
Jens
....
ahc0 at pci7 dev 2 function 0 vendor "Adaptec", unknown product 0x0082
rev 0x02: apic 7 int 21
scsibus0 at ahc0: 8 targets, initiator 7
sd0 at scsibus0 targ 6 lun 0:<FUJITSU, MCJ3230SS, 0010> SCSI2 0/direct
removable
holy cow. haven't seen one of those in a machine in a while. :)
(ok, actually, I don't think I've ever seen one, period. Or maybe I've
got one...)
....
Nick.
Dear Mailing Listeners,
Thanks to all who answered to my question to make their SSD knowledge
clear to me.
@Nick: You want to know more about my oldtimer? Oh, it's just 13 years
old, and
if it should fail once a day it will be replaced by its predecessor
MCR3230SS
which is five years younger ... Thanks to the work of Kenneth R.
Westerback these
devices work reliable even with media having sector sizes of 2048 bytes.
Greetings,
Jens
