WOW!!!! $15k DEC PDP-8 CLASSIC MINICOMPUTER SYSTEM DIGITAL PDP8

Brad> Vintage Computer Festival wrote: Brad> My experience is the S/360 & 370's machines ran 24x7 and there Brad> was little time left over for hacking. But if you got to be Brad> friends with the operators and read all the manuals and what Brad> source code you could find, you could do some pretty fun hacks. I've had some operator time in college on a 360 model 44 (running OS/PCP, which was unusual since most 44s ran an OS specific to that machine -- it didn't normally have a full 360 instruction set). It belonged to a nearby grad school, and didn't run anywhere near 24x7. So powering it on and off was part of the experience. I had some fun hacks on it. The console wasn't considered a normal I/O device (it had no name so programs couldn't reference it in the usual way). But if you constructed a few of the relevant data structures "by hand" you could read/write it just fine. So I messed up all the UI conventions by doing exactly that. The other hack was a switch into supervisor mode from my application (the WATFOR compiler, actually...) to install a patch into the kernel to capture an interrupt (some operator panel button). It was really easy, quite obvious from reading the manuals. I found out later in grad school that the same security bug was still around in OS/MVS 21.x. Didn't use it there (verified it existed but resisted the temptation to exploit it). Lastly, there was the 360 program for reading and printing PDP-11 DOS formatted tapes... including search by name, something OS/360 could not do even for native tapes... I wish I still had that program, but no such luck, not even a listing. So yes, you could hack those machines if they weren't too large and you were in the right spot. But I'll agree that I'd grab a PDP-11 way before I'd be tempted by a 360. paul