Excellent! That worked great. Do I also need DU.SYS or can I get rid of that? Thanks, David

On 10/4/07 20:37, "Jay West" <jwest at classiccmp.org> wrote: I should've spotted that too. Doh :) -- Adrian/Witchy Binary Dinosaurs creator/curator Www.binarydinosaurs.co.uk - the UK's biggest private home computer collection?

On 4/10/07, David Betz <dbetz at xlisper.com> wrote: Well done. That's the first partition. It's still there, lurking. RT-11 uses, IIRC, 16-bit block pointers... 65536 x 512 bytes == 32MB, the largest swath of a big drive it can grab in one chunk. I've never personally run RT-11 with a disk over 32MB, so I don't know how it's done, but I know it can be done. It might or might not depend on what version of RT-11 you have. I *think* if you have MSCP support, you always have the ability to have multiple partitions on your large drives, but someone with experience on new(ish) hardware should chime in. The largest machine I ever ran at home was an 11/23 with a couple of RL drives. When I did use RT-11 on an 11/73 with a large disk, it was under TSX-11, and without the docs in front of me, I'd hesitate to quote technique from memory. You should be able to find what you are looking for in the RT-11 docs for versions of RT-11 > 5.4, at least. Dunno about < 5.4. -ethan

Jerome Fine replies: I think you are confusing the use of the LDX.SYS logical device driver along with dividing the 32 MB hard drive partitions into files, each of which have their own RT-11 directory, and the DUX.SYS device driver which has about 159 MB or about 5 RT-11 partitions. I agree that 65535 blocks for an RT-11 device is usually far too large for a single RT-11 directory when the maximum number of files is about 2000 files per RT-11 directory in any case. BUT, using LDX.SYS is very separate, in my opinion, from how DUX.SYS divides the RD54 into 5 RT-11 partitions. Of course, if you have a 2 GB hard drive (or SIMH with a file) which can hold 64 RT-11 partitions, then starting with V05.05 of RT-11, extended DU(X).SYS allowed 64 RT-11 partitions to be available at the SAME time. And if you have a hard drive or a file of 8 GB, then 256 RT-11 partitions are available in total via the: SET DUn: UNIT=u, PART=255 except that a maximum of only 8 RT-11 partitions can be specified in each DU(X).SYS device driver at one time with V05.03 of RT-11. I doubt VERY much that anyone is interested in a larger number of RT-11 partitions per DU(X).SYS device driver, but it would be fairly easy to allow up to 65536 RT-11 partitions for each unit, just not all at the same time. At the moment, the 2 word internal table allows 16 bits for the UNIT, 8 bits for the PART and 8 bits for the PORT (physical controller or host adapter). Since I have never EVER seen a UNIT of larger than 255 used, the switch between UNIT and PART would be easy, especially since a value of n > 255 is not allowed in the SET command in any case. Starting with V05.03 of RT-11, DU(X).SYS allowed a large hard disk drive (> 32MB) to be divided into 32 MB RT-11 partitions, or more specifically, for the portions of the hard drive beyond 32 MB to be accessed as RT-11 partitions. The MSCP DU(X).SYS device driver first became available (with a few bugs that were fixed by V05.03 of RT-11) with V05.00 of RT-11 in 1983. V05.03 of RT-11 was released in 1985. LD(X).SYS was released with V05.00 in 1983. It was an integrated device driver (with RT-11) of a DECUS device driver that had been available for many years. I suppose that DEC finally realized that if DECUS people could do the code, then DEC had better do the integrated job when V05.00 was released. Since V04.00 did not know when physical devices were being used, if the hard drive files were "SQUEEZED", especially on the system device, all of the pointers had to be reset to the logical devices. Not a difficult coding problem, but changes were required in V05.00 to allow for LD(X).SYS to function correctly. In general, LD(X).SYS provided RT-11 with a set of sub-directories. What is still missing from RT-11 is what VMS has called Logical Name List - or what I suggest in RT-11 be called the Symbolic Translation device driver with a name of ST(X).SYS which would allow what DOS calls a PATH NAME list. However, ST(X).SYS would apply to ALL EXISTING files being opened via the .LookUp EMT and the user would be allowed to specify up to 16 physical devices for each unit in the Symbolic Translation device driver, i.e. ST3: => DU0:, DU1:, LD0:, LD1:, etc. SET ST3: DEVICEA=DU0 SET ST3: DEVICEB=DU1 SET ST3: DEVICEC=LD0 SET ST3: DEVICED=LD1 A .LookUp EMT request for ST3:FOOBAR.TST would check all of the specified physical device names in the order specified before returning a File Not Found error. 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.

Okay, I think I see how to do it: set du0 unit=0, part=0 set du1 unit=0, part=1 set du2 unit=0, part=2 set du3 unit=0, part=3 If I do this, I wonder where my RX33 will be assigned. Is it assigned du4 since du0-3 are already taken by partitions?

An RX33 is a 1.2mb 5.25" floppy drive. Actually, I guess I just didn't think hard enough. When I didn't have *any* set commands, the drives were automatically assigned DU0=RD54 and DU1=RX33. My guess then is that the RD54 is unit 0 and the RX33 is unit 1. The suggests that if I just add the line: set du4 unit=1 I should get the RX33 assigned to DU4: I guess I should think before I type in questions. Sorry!

Hi Jerome, Ah! That nearly drove me mad already..... Much frustration.... Could you provide me a copy of your "best" RT11 distribution? I can receive large email without problem. Would be nice, thank you. Best regards, Philipp :-)