#: 6800 S3/Languages
    19-Sep-90  23:19:30
Sb: #6799-C Libraries
Fm: Kevin Darling (UG Pres) 76703,4227
To: Greg Morse 72746,3451

Greg - this is offhand, but...

No, I cheated badly and didn't use F$MapBlk at all, so someone did some
extensive changes in the version you have.  In any case, ummmm, OS9 doesn't
keep any blocks in the system map free.  So if the MapBlk could fail if things
are hot and heavy (less so in your 4K system of course).

The kernel's F$LDABX etc commands are hardcoded to directly map in the desired
external block at logical $0000 in the system map... for speed, and because OS9
always knows that block 00 is located there.  That is, it can always zap the
DAT to grab/write a byte, and reset that first DAT block to 00 with impunity. 
Of course, it shuts off interrupts before doing so .  Thus a driver which
does the same thing is cool, just not useable on other hardware (just as the
kernel isn't).

Sounds like fun (messing with Pipeman)... good idea, too, as Pipes are rather
slow, as you said.  Yell if you need anything! best - kev