From: "Doc Shipley" <doc(a)mdrconsult.com> Lucky you. I have 1 or 2 too, but they are getting hard to find (in Europe anyhow) Correct Yes, physically. The drive as such is stupid, so it will depend on your drivers It can read and write anything from SSSD (= 251K) to DSDD (1.1 M) Remember though, that track 0 always is formatted as SSSD. Contact me if you need more info Nico

Hi Doc, I have a PDF copy of the YD-180 drive if you need it. FWIW in the General Information section of the manual they state that it's compatible with the IBM 3740 drive so it should certainly handle that format. Joe At 09:55 PM 1/24/04 -0600, you wrote:

Jerome Fine replies: To start with, first let me say that I understand too little about hardware issues to be of much help. As for the 8" RX02 floppy format, remember that only the data is Double Density, the header is still Single Density. Also, as far as I know, ONLY DEC systems used and could handle the SSDD (Single Sided Double Density) RX02 format. I am not aware of any other computers and operating systems that used the RX02, except if you consider the 3rd party manufactures of DEC compatible hardware. In that regard, DSD (Data Systems Design) was one of the companies which sold a number of RX02 compatible systems, including the DSD 880/30 which had both an 8" hard drive that emulated 3 * RL02 (but in this case non-removable) drives and a single RX02 drive as opposed the the usual dual RX02 drives from DEC. I still have a couple of DSD 880/30 systems that might still work. On occasion when I need to read an 8" floppy, I use them. One aspect of the DSD 880/30 is that the hardware is also RX03 compatible, although DEC never actually sold an RX03 floppy drive. BUT, if there were some 8" drives, if my failing memory serves me correctly, which could be attached to an M8029 DEC Qbus board (the company that made plotters) that would allow both sides of the 8" floppy to be read. The definition of an RX03 was DSDD (Double Sided Double Density), as far as I know. In any case, the DSD 880/30 has the hardware to use both sides of an 8" floppy, although like the DEC M8029 controller, the controller for the DSD 880/30 is also limited to just 18 bit addresses for transfers to/from the DMA Silo or a range of 256 KBytes of lower memory. Formatting an RX02 could be done in one step using the DSD 880/30 OFF-LINE to format the floppy as SSDD. In addition, if an 8" floppy was already formatted as SSSD, then RT-11 was able to send a command to the header to make that 8" floppy able to accept SSDD data. Thus the RT-11 command: FORMAT DY0: did not actually do a complete LLF format, it was only able to change an 8" floppy with an already existing SSSD LLF to a SSDD LLF, i.e. change the header flag from Single to Double Density. The DEC RX02 drive was unable to do any LLF at all. It was able to accept the command under RT-11: FORMAT DY0: I did manage, by the way, to add a DPDT switch to the floppy drive in the DSD 880/30 which reversed the sensors used to detect a Single Sided floppy as opposed to a Double Sided Floppy. That allowed me to use ALL SSDD RX02 floppy media as DSDD floppy media without having to punch the extra holes. In my experience, the ONLY floppy media I ever found a problem with were 8" floppies from DEC distributions of software. Some one had used software distribution floppies from DEC and I thought it would be worth while to try them. About 20% did not work as DSDD. Not all blocks were bad, but a few in some cases. As far as I know, the IBM 3740 format was SSSD or equivalent to the DEC RX01, or more to the point the other way around. You need either a DSD 440 or a DSD 880 or any of the other 8" compatible 3rd party systems. The DEC RX01 / RX02 hardware could NOT do an LLF. YES!! But remember that a DSD 440 and a DSD 880 is rather heavy. If an LLF is a one time requirement, then it would be less expensive to ship a few floppies around. If you can find someone near by with a DSD system, that would be best. By the way, V4.00 of RT-11 did have incorrect code to handle the Double Density option for an RX03, but in V5.00, that code was removed. I did manage to modify DY.MAC for V5.03 of RT-11 to use a DSDD RX03 floppy PLUS use a bounce buffer in low memory so that all 4 MBytes of memory under V5.00 of RT-11 could be used by DYX.SYS for the user buffer. I have mentioned this last part many times, but by now too few people have a DSD 880/30 system around, let alone use it with V5.00 of RT-11 and later. Sincerely yours, Jerome Fine -- If you attempted to send a reply and the original e-mail address has been discontinued due a high volume of junk e-mail, then the semi-permanent e-mail address can be obtained by replacing the four characters preceding the 'at' with the four digits of the current year.