[EMAIL PROTECTED] wrote:
>
>
> >BTW: a lot of numbers in Solaris did not grow since a long time and
> >thus create problems now. Just think about the maxphys values....
> >63 kB on x86 does not even allow to write a single BluRay disk sector
> >with a single transfer.
>
>
> Any "fixed value" will soon be too small (think about ufs_throttles,
> socket buffers, etc)
The maxphys limit of 56kB or 63kB in the early 1980s was a result of the
fact that many DMA controllers could only handle 16 Bit counters and because
(on a multi-tasking environment) a typical DMA speed of 600 kB/s would result
in ~ 0.1 seconds of wait time for other users.
In 1980, Disk sector sizes have been 512 bytes.
In 1995, the DVD was introduced with 32 kB sector size.
Now we have BluRay disks with 64 kB sector size.
On many systems, cdrecord cannot write a single BLuRay sector in a single
SCSI transfer. This is bad.
With today's constraints, I would expect to see typical maxphys values of ~ 2
MB.
Linux typically allows this but Solaris does not. In addition, the ioctl
DKIOCINFO in many cases returns wrong (too big) numbers for maxphys which causes
cdrecord to fail. Solaris needs to aproach today's reality with some parameters.
Jörg
--
EMail:[EMAIL PROTECTED] (home) Jörg Schilling D-13353 Berlin
[EMAIL PROTECTED] (uni)
[EMAIL PROTECTED] (work) Blog: http://schily.blogspot.com/
URL: http://cdrecord.berlios.de/private/ ftp://ftp.berlios.de/pub/schily
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