On Fri, 24 Aug 2012, Liam Proven wrote: There either needs to be a ROM, or key in enough code to load from disk. Do you consider the "system track[s]" that are NOT represented in the DIRectory to be "FILE[s]"?

Seems like a deal for $200. http://www.ebay.com/itm/HEWLETT-PACKARD-2108A-21MX-COMPUTER-SERIES-VINTAGE-…

On 8/24/2012 4:34 PM, Mike Loewen wrote: If you collected them I'd say the case and front panel was probably worth that. It is gone now anyway. Hopefully someone here grabbed it. I would have bought it myself but, I'm too poor. No new old computers for me for now. Probably a good thing.

The Commodore 900 ("Z-Machine") used the Z8K, and there are a couple others. -- ------------------------------------ personal: http://www.cameronkaiser.com/ -- Cameron Kaiser * Floodgap Systems * www.floodgap.com * ckaiser at floodgap.com -- Conscience makes egotists of us all. -- Oscar Wilde ------------------------

On 08/24/2012 05:21 PM, Fred Cisin wrote: There was always a boot rom somewhere that loaded the loader. However it was possible to put CP/M in rom and use that with disks that had no system track (and usually more space on disk). The Epson PX8 did that, its in rom and copied to ram. That saved having system on a disk and for the Ramdisk saved having to preserve system tracks. IT's down side is it's harder to add stuff to the BIOS (they did leave hooks). I did it in different way where the minimal bios and bdos was configured to load in mid ram and added to a block of code that replaced the CCP loaded from from rom to ram. That then loaded to high ram CPMBIO.SYS and CPMBDOS.SYS and CPMCCP.SYS from disk files in the directory area. This allowed me to replace them easily without resorting to a monolithic system track loader and it made adding new BIOS features or experimenting with things like P2dos, ZCCP, and ZCPR easily. It also meant that a very crude BIOS that only knows about the disk system was needed to boot a flexible and configurable system and it only needed 8K of rom of which the CPM-boot was 6K and 2k for a system debug monitor. That was only one way to do that. For my AmproLB+ I let it load the system in the very conventional way and use a program called sysload that would load any file into the CCP, BDOS, BIOS memory areas as desired and could be a .BAT file with the load command. I used that during the bios rework for the SCSI disk and then to include ZCPR features without the worry of system tracks that might not boot. There is as I've said on COM.OS.CPM and elsewhere, there are very few limits on how one could boot and configure a CP/M system, other that when done the system has the first 256bytes as per the book and the TPA starts at 100H to look and act like a normal CP/M system. Allison

On 08/24/2012 06:53 PM, Dave McGuire wrote: That is usually true and usually done that way but there is no specific requirement to do that. Only that all the examples do that. The reason they did it that way was twofold big Eproms were scarce and expensive when they first became available in the early days and you need a OS to read a file system. Allison