HP IPC (update)

This is the information I have managed to gather on the HP IPC: First have a look at the definitive guide to the IPC (http://www.coho.org/~pete/IPC/integral.html) Apart from that, I have managed to find the following info by playing with my IPC: There is a ROM at the back behind a little door. This contains basically the Unix OS (HP UX) and at least in my case Tech Basic. Tech Basic looks surprisingly like Series 80 Basic (e.g the Basic on the HP-86 and 87) including many ROM additions (e.g. IO ROM). The funny connector on the back (like a small centronics connector) is HP-IB (the HP name for IEEE-488) which is used to connect peripherals like floppies and hard disks. The IPC talks CS/80 over HP-IB so it supports "modern" HP-IB peripherals like the 9122 floppy drive. The IPC also has in internal HP-IL bus (a two wire, low power version of HP-IB) which is used to talk to the built in printer. At this stage I haven't managed to investigate whether I can externalize this bus and connect additional peripherals. The built-in printer takes hp92261a print cartridges which (amazingly) are still available from major mail order firms (e.g. www.staples.com in the US, but I suppose you can get them in the UK as well). Since the print cartridge contains the print head as well, it is very probable that you can get the printer to work with little effort. The IPC site (see URL earlier on) has a number of diskette images. These are for double sided double density (720K) disks. I have been unable to get any modern PC to write compatible floppies using the standard double sided quad density drive (1.44Mb). I did find a 720K drive on eBay and bought a pack of 720K diskettes. Using OpenBSD on a PC I then proceeded to successfully transfer the images to the floppies and access the data from the IPC. BTW the IPC utilities in the IPC site (programs that can be used to read IPC floppies on a Unix host) work only on big-endian machines. You cannot use them on a i386. Before trying to use the built-in floppy drive, note the following: a) its totally non-standard. The connector is wrong and the RPM is wrong. I believe there is no way that you can use a PC compatible drive on that machine. So take good care of it! b) the heads need cleaning and the loading mechanism needs lubricating. If you haven't done this already, do NOT skip this step, you may damage the disk heads if you try to use a drive with a sticky loading mechanism. See later on for cleaning instructions. c) The built-in disk notifies the OS when a new diskette is inserted so that it is automatically mounted. This makes the built in floppy more convenient than external devices. Using the system: Just power it up and you should see the unix boot messages. Finally you see the desktop manager (PAM). You can type paths on the command line on top or use the cursor keys to navigate the file system. If you have an HP-HIL mouse so much the better you just point and click. You should find the BASIC interpreter in /rom/basic. Until you get the floppies from Peter's site, BASIC is the only way to use the machine. Use MASS STORAGE IS path to change your working directory and CAT path to list directories. If you need documentation on Tech BASIC, I suggest you buy an HP-86/87 Owner's manual on eBay. They are close to the real thing and far more common than IPC manuals. For a hint on how to use external peripherals check the file /documents/hp71_xfer on the IPC_BASIC_Bonus diskette. As an example, here is a program that collects readings from an HP multimeter (HP-IB device 13). 100 ! load HP-IB driver 110 MASS STORAGE IS "/dev" 120 ! on Series 80 the HP-IB card is always number 7 130 ASSIGN 7 TO "hpib" 140 ! The 13th HP-IB device is therefore 713 150 m=713 160 ! switch multimeter to remote control 170 REMOTE m 180 ! program multimeter for resistance, auto zero and trigger mode 190 OUTPUT m; "F3R1Z1T2" 200 ! initialize "previous" reading 210 v0=-1 215 DISP "Ready: press STOP to terminate program" 220 ! do while true 230 TRIGGER m 240 ENTER m; S$ 250 ! display value only if different from earlier reading 260 IF v0<>v THEN DISP v 270 v0=v 280 GOTO 220 -------------------------------------------------------------------- Drive removal: Get a torx #10 screwdriver, almost all the screws on the IPC are of this type so there is no point in trying to do any maintenance without one. The plastic diskette eject button seen from the front of the machine, is not attached to the drive and is likely to fall off when you remove the drive. It is best to secure it in place by covering it with a small piece of adhesive tape. This will keep it in place during the removal and subsequent installation of the diskette drive. First remove the back panel. You do NOT need to remove the system ROM to do this, so leave it alone. The panel is held by just two screws (probably the only screws that need a flat blade screwdriver) and hinges on the bottom of the machine. Once the panel is removed you can see the inside of the machine. A big PCB to the left and the floppy to the right. Open the printer door (on the top of the machine) and look at the bottom of the storage compartment next to the printer. You should see two black screws. Remove them. Now the only screw holding the diskette assembly is on screw on the bottom of the assembly (right on top of the PSU). remove the connectors and the last screw. The floppy should slide out towards you. Looking at the the floppy assembly you see a mounting bracket and a full height floppy. Before removing the drive from the mounting bracket mark the orientation of the floppy drive against the bracket with a pencil this will make reassembly easier. Remove the mounting bracket and the metal cover of the floppy. Do not forget to remove a black screw on the back of the floppy, otherwise you will not be able to slide the metal cover out. You should see the loading mechanism on the sides of the floppy. Try inserting a diskette to see how it causes the loading tray to slide along paths on the fixed sides of the drive. These are the only parts that need cleaning and oiling. Use machine lubricating oil (under no circumstances should you use stuff like WD-40). Apply one or two drops on each side and insert/remove the floppy until it slides in and out effortlessly. I use a cleaning floppy to clean the heads, so there is nothing more to do at this stage other than closely inspect the READ/WRITE heads. Hopefully they should have the obvious orientation that allows them to come into contact with the magnetic surface of the floppy. If this is so, then you are in luck, otherwise you lose. Replace the cover and secure the floppy on the mounting bracket. Orient the drive and bracket so that the two screw holes are on top and slide the entire assembly inside the IPC. Attach the top two screws and the bottom screw. You may need to slightly adjust the drive mounting assembly to align the bottom screw. Replace the power and data cables and reattack the back panel. Remove the piece of adhesive tape securing the eject button and you are ready. --------------- Corrections or additions are always welcome. **vp