> There's also the fact that your cheapo-cheapo PC has one processor and has to
> do all the I/O for itself. The PC's processor spends 90% of its time handli
> ng I/O, formatting data for some port or the screen, running a driver program
> , polling and waiting for a response from some peripheral and so on.
>
I don't pretend that my Athlon-based system's overall design is anything like as
good as the S370/168 I used to use so many years ago, but fair go.
My PC has the on-board EIDE interfaces (EIDE{0,1}) and additionally, an add-on
PCI card providing two more EIDE ports.
At one time I had three drives in the box on each of three interfaces. I was
running DD to do a disk-to-disk copy, and while it was running, I used hdparm to
test the speed of the third drive. It tested at 35 Mbytes/sec, pretty close to
its rated speed.
My graphics card has its own processor, and if I add a SCSI card that too
offloads a decent amount of work.
Devices use interrupts to signal the end of operations, and many use DMA devices
to provide direct access to system RAM.
While IBM's mainframes do all these things better (except compute), if an IA32
system uses more than about five percent of the CPU power to drive devices, the
OS is broken.
On Linux, we use (mostly) the same software you do. It does not need lots of CPU
power to drive most I/O devices.
--
Cheers
John Summerfield
Microsoft's most solid OS: http://www.geocities.com/rcwoolley/
Note: mail delivered to me is deemed to be intended for me, for my disposition.
==============================
If you don't like being told you're wrong,
be right!
