🚀 go-pugleaf

In article <1993Jan23.231824.24755@rose.com> gyl.midroni@rose.com (gyl midroni) writes:
>
>Date Entered: 01-23-93 18:08
>C(> 
>C(> >Didn't he say it was a VL card?  That means that the CPU can't do
>C(> >anything anyway, since when the disk controller has the local bus the
>C(> >CPU can't talk to memory or anything anyway.  This is why I don't see
>C(> >VL as a real win for anything except perhaps video; it will give you
>C(> >great burst mode numbers, but it impacts overall system performance to
>C(> >do that.  
>C(> 
>C(> Hmmm, it still has the internal I/D cache to run out of.
>
>    Could you explain this to me a little slower please?  I am about 
>to plunk down big bucks on a new system.  This particular vendor 
>offers local bus hard disk controller.  He says the bus is 100% VESA 
>compatible.  
>    It seems to me that local bus disk access will be a speed booster 
>for the reason of faster data communicatio with the CPU / memory.  It 
>is four times faster to get data off the disk at 33 MHz off the local 
>bus connection to the CPU and memory than at 8 MHz via the ISA bus. 
>As simple as that... no?   Why would this impact system performance 
>any more than getting data off the ISA bus.

First of all, bus master DMA on the ISA bus (which is a local bus, just
for the 286 instead of the 486) _will_ prevent the CPU from accessing
main memory. The big deal about having a faster bus is that on a hard
drive transfer (for example) instead of the CPU grinding to a halt
(because the bus is being used to capacity) it may still run at
80% of peak performance. This is a big deal if you're using a
multitasking OS like OS/2 or whatever.

Dan