danm@mspiggy.UUCP (10/28/83)
In trying to write a device driver for a hard disk on my CoCo under RS's version of OS/9 (Microware version 1.2), I kept getting access permission errors (#203, I believe). I called RS about this (their technical hotline is (817) 390-3944). They were unable to help me. So I called Microware. It turns out that the RS documentation omits to mention that you need to include the access code in the device driver ** as well ** as the device descriptor. This access code should immediately follow the MOD statement that begins the device driver code. This is the same code that the device descriptor uses. Without this code in both modules, you will get access permission errors. Another interesting fact that I learned is that RS V1.00 (as well as Microware V1.2) place no restrictions on sector allocation map size. This means that if you are using disks with capacity greater than 1M, no special provisions need to be made for that. The RS documentation states that the size of the sect. alloc. map must be less than 4096 bits. To handle large disks, you grouped sectors into clusters, with the number of sectors per cluster being specified in the device descriptor. Unfortunately, this is an artifact of Microware OS/9 V1.1 and earlier. This restriction doesn't apply to RS OS/9. This field is ignored by FORMAT and the rest of the software (actually, FORMAT sets it to 1 in sect 0, track 0 and calculates the rest of the parameters correctly). The result is that you can ignore that actual value of this field (but make sure you reserve space for it in the descriptor). Hope this helps anyone else who has had dev driver problems, Happy hacking, Dan McCabe decvax!microsof!danm
dyer@wivax.UUCP (Stephen Dyer) (10/29/83)
HARD DISK FOR YOUR COCO???? Pant, pant, droool... Where did you get it, what's the controller, how much does it cost, and how the hell could you even to begin to write a device driver after just reading the R/S OS-9 manuals? I've been reading them and find them pretty obscure. It's funny, feeling like a beginner again (no more jokes about INFO-UNIX and 'net.unix', no sirree.) Anyway, I'm sure we all would love to hear more about the hard disk and your progress on a driver for it. In the meantime, I would especially like to be able to modify the floppy disk formatter and device driver so that I can access all 40 tracks and both sides of my Remex disk drive as /d1. I am using a modified cable from FHL which uses side-select (unlike the standard R/S cable which uses it as drive 3 select.) Also, how do you install /d2, if you have three floppy drives? Anyone with pointers or insight into the manuals, please drop me a line. Best, Steve Dyer decvax!bbncca!sdyer