Tony Duell's maxed out 5160 and PDP

Actually, I forgot about the scond disk controller, which means the thing can actually have 6 floppy drives. However, the last 2 are not accessible As for the 4 normal drives, I have the original IBM controller board. This has an edge conenctor at the front fro a nromal cable (with the 'IBM twist') to connect it to the 2 internal 360K (full height) 5.25" drives. On the rear bracket of that controller is a DC37 connector which takes another cable with an 'IBM twist' to link to 2 exteranal 720K 3.5" drives. [...] Well, MS-DOS for a start, along with BASIC. And quite a few other things besides. boards in this machine are : -- A clone XT multi-IO card, modified. This provides 2 of the serial ports, a parallel port, a joystick port, and originally a floppy controller. I replaced the single chip for that with a pin-compatible PC/AT disk controller chip, changed the clock crystal, and modified the address decoding to put it ant another address. This is the 'extra' disk cotnroller that I ahve hooked up to a pair of 8" drives -- A I2C interface (Elektor design), based o nthe PCF8584 chip -- Hard disk controller -- MDA card -- CGA card -- Standard floppy controller -- Dual serial card -- 8255 24 line user port (Maplin kit) Of course I've done the normal modification ot the motherboard to put 640K of RAM on there. I was quite lucky. I managed to find another PC/XT (IBM 5160) which was _all_ original IBM. From what I recall, it has a CGA card, floppy controller, Async serial card, parallel card, one 360K floppy drive and.... the expansion unit contianing 2 hard drives and the controller for them. Oh, and origianl IBM 5153 CGA monitor too. I think so. If not, I've got plenty of other machines where you get to see the cores. Indeed... Non volatile, but reading is destructive :-) Itwould probably be caleld BASIC these days, becasue so many languages seem to be :-( I bought the first 28C I saw -- back when it was new, and I was an undergrad at the time. Really cut into my budget. A few yers later, I ordered a 48SX the day it was announced, that machine cured the major problem I had with the 28C, namely no way to back it up (the 48SX hasa serial port, of course). nd then some yeras later I made the big mistake of buying a 49G. That machine was not, IMHO 'of merchantable quality' when I bought it. There were so many bugs in the first few ROM releases (flash upgradable, thankfully). Heck, the version that was in the machine when I bought it would return a dot product when you executed the cross product function. Advertised features simply did not exist in the first few ROM versions. What makes it worse is that I wrote a letter of complaint to HP. They didn't bother to reply. I sent them a further letter, enclosing IRCs. They didn't reply again. And for that reason. while I will happily restore and use classic HP amchines, I will never buy another new product Yes, it is very useful, as is the arbirary size stack of any types of object (the older machines had a 4 level stack of real numbers only). Not many machines allow you to build up a string on the stack, and then execute it as a program. -tony