ingoldsby@calgary.UUCP (Terry Ingoldsby) (11/22/86)
A few weeks ago I posted a RAMdisk driver for use with the CoCoIII and OS9 (level 1). The author reports a small bug when used with 512K CoCos. Here follows the complete description and fix. There is a bug in the ramdisk driver ccrdisk as posted recently. There is no problem on 128K coco's, but after installing my 512K upgrade a few hours ago, i realized that the ramdisk doesn't work if you put more than 64K on the ramdisk. The problem was that i was ignoring the top 3 bits when computing the phys address of a secotor. Anyway, to correct the problem, simply replace the function 'doseek' in the driver "ccrdisk" with the one below, and you are all set (finally) for up to 440K of ram disk space! You get around 75K/sec IO rate at 1.8 Mhz! Let's see your favorite hard disk do that on a continuous basis! NO, eagles don't count... unless you have one on your coco3!? doseek pshs d tstb bne e.lsn cmpx dd.tot+1,u bhs e.lsn tfr x,d lslb rola lslb rola lslb rola adda physbase cmpa #MAGICPG (skip over this one!) blo doseek.2 inca doseek.2 sta track tfr x,d tfr b,a anda #$1f adda #RAMBASE/256 clrb std rdbuf puls d,pc e.lsn *this last label for reference ----------------------------------------------------------------------------- Refer all comments and inquiries to me and I will pass them on to the author. Terry Ingoldsby ...ihnp4!alberta!calgary!ingoldsby