<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <HTML><HEAD> <META http-equiv=Content-Type content="text/html; charset=iso-8859-1"> <META content="MSHTML 6.00.2800.1528" name=GENERATOR> <STYLE></STYLE> </HEAD> <BODY bgColor=#ffffff> <DIV>Hi Dwight Thanks (again) for your valuable assistance! BTW I hope you are feeling better now. Unfortunately due to my job I don't get much free time to spend on my hobby, but this weekend I was able to finally spend a couple of hours in my workshop and got to the bottom of the serial problem I was having! At last I have your disk transfer program working fine now! The cause of the lack of serial comms was actually that the 8250 itself was faulty. Talk about bad luck; I had originally discounted the serial card having a hardware fault because I tried swapped serial cards between my two H89s and this had not fixed the fault. As it turns out, BOTH the serial cards had duff 8250s in the LP port circuit ! In the end, I swapped an 8250 from one of the other ports on the card to the LP section and your loader started to work fine. I can't imagine why the 8250s on the LP port on both machines should have both suffered the same fate; the line drivers associated with the LP port on both serial cards are absolutely fine. I'd have thought that if someone has mis-connected the LP port on both machines, or subjected it to static discharge the line drivers would have been the first to go! There was one other problem that's worth mentioning for those who also want to use your H89TRANS. On my pure DOS machine I have Windows 3.1 installed and as is usual with Win3.1 installations, I also have SmartDrive installed. When I initially got your loader program communicating I found that at some random point during the transfer of data between the H89 and the DOS PC, the communication would suddenly stop. However, when using the floppy drive (on the DOS PC) as the source or destination, the problem did not occur. I found that not loading SMARTDRV.SYS on the DOS PC fixed this and allowed the data transfer to complete successfully. I've now saved the loader on the H89 to a new disk successfully so I don't have to re-enter the loader into the H89 each time. Also have successfully 'imaged' one of my original disks and have written it back to another (blank but INITed) disk with no problems. I've only two disks that came with the machines, both are HDOS with INIT, SYSGEN and one has BASIC, so I'm looking forward to playing with some of the images that are now in the archive. I also got myself a Z80 assembler (freeware) from Programmer's Heaven which works fine (I converted your source listing for the loader from 8080 to Z80 opcodes successfully and it generates an exact (hex) listing to your octal listing for your 42 byte loader which was reassuring!). BTW, another approach I thought about trying was to use a different serial port in your loader program by changing the base address (0xE0) but I can't find a map of I/O addresses for devices in the H89, is there a definitive list somewhere? Also, can you (or anyone) explain the significance of the volume number to me? Your program allows you to set (override) a volume number or take it from a disk image. I assume that this is the 'unique volume number' that you are asked to input (from 1 - 255) when INITialising a disk. What is the importance of this (i.e. will setting the wrong volume number when creating an actual disk mean that the disk won't work?). Thanks again for your help! Regards Robin </DIV></BODY></HTML>