Good question. Unfortunately I don't know the answer. Anyone else know? Terry (Tez) On Tue, May 28, 2013 at 2:46 AM, geneb <geneb at deltasoft.com> wrote:

Tez...It is just me or it looks like an Epson printer? :oD The main CPU looks just like a MX100 without the top opening! :D :D :D

On Tue, 28 May 2013, Jules Richardson wrote: I'm surprised he didn't stick RAM in the empty sockets as soon as he discovered them. :) g. -- Proud owner of F-15C 80-0007 http://www.f15sim.com - The only one of its kind. http://www.diy-cockpits.org/coll - Go Collimated or Go Home. Some people collect things for a hobby. Geeks collect hobbies. ScarletDME - The red hot Data Management Environment A Multi-Value database for the masses, not the classes. http://www.scarletdme.org - Get it _today_!

When you need chips, ask me or any brazilian friend. 2114, 2112, 4116, 4416, 4164, 4464, 41256, 44256, 441000 are still cheap and easy-to-find chips here. I may have some 1000 4164 in my stash.

On 05/29/2013 01:28 PM, Tony Duell wrote: I always think of it as a bit 'cute' - CP/M machines should be in big metal crates with backplanes and separate boards for different functional areas! :-) From a design point of view it does seem well thought out, though. Yes, they're wonderful little things, but I do worry about how robust they might be (and how easy it is to obtain* spares should one die in some horrible way). I am tempted to disconnect them and run the data cable - via a socket in one of the expansion bay positions - to a pair of external half-height drives (also useful because it's a pain having to dismantle the system to clean the internal drive heads every time a disk decides to dump its coating everywhere) * I'm not sure if the 1/3 height drives that Torch used in some of their systems are the same - if they are, I possibly still have some of those in overseas storage. At some point I need to take a look at my system, as it occasionally resets itself (seemingly at random) - that may be a PSU problem, but could of course be various other things, too. It's infrequent right now (maybe once in a couple of hours of running) - perhaps too infrequent to make diagnosis easy! Mine actually has '4164' silk-screened on the PCB for all the memory locations (and does indeed have 4164's fitted in the sockets). It looks like there are six links on the board; three are set for 64k DRAMs and the other three set if using 16k ones. That's interesting... my board has obvious pads for a cap at the top end of each DRAM, but no caps fitted in those locations (there do look to be decoupling caps for the memory elsewhere, of course). Yes, I don't see any *obvious* jumpers etc. related to this (my system's got 256K; I think most of the ones in the US shipped like that). They're 4864's in mine. cheers Jules

Right... I aswas never realyl into S100 systems (actually, I was, and am not, into CP/M elther, much prefereing LDOS as a Z80 OS). Most of the CP/M machines I do own are pre-configured thignsl ike the QX10 and the HP120 (which is one of my least favourite HPs, although it's nice in a quirky sort of way). I suspoepct that spares are about as easy to obtain as for most floppy drives :-(. Have you tried to order repalcement heads for any drive recently? More seriously. yes, the heads can waar out, and they are unobtaianble. There are a couple of ASICs in the control system, but I;'ve never hadn them fail. It is possibe to rebuild the positioend nad spindle motor, but it's a lot of work. I guess the most likely thign to fail is the dribve belt, I am sure that can be kludged. [...] The drives in the XXX, Graduate, etc are Epson, but they're half-height and use a stepper motor to move the heads. They also ahve a direct-drive spindle IITC. There are schematics for them in my XXX diagrams if I gave you a set of those. But I don;t think any non-triivla parts exchange with the drives in the QX10 -tony

I certainly like an expansion bus, and, in fact, one of the things I dsilike about anything remotely recent is that either there's no expanison bos or if there is it's very difficult to interface to. So, yes, I do like I/O slots. But after that, since I never realy work at the board level, I don't much care whether there's a large motherboard with a few expansion slots on it (like the QX10) or a passive backpale nwit hte CPU, memroy, etc, boards plugged in (like an S100 system). [Epson disk drives] Why on earth would you even think of repalcing a compelte drive? Ouch!. Wabash disks were pretty awful, but I never had one actually damage a drive. When I was at school, at first you had to use floppy disks bought fro mthe school and they were Wabash :-(. Ouch!. In the end they let us use disks from elsewhere (like the assortment of Inmac Pluss, Berbatim, Dysan, etc that I had...) but they were totally clueless, saying things like 'If you use single sided disks, do not attempt to format the other side (remember the 380Z treats a double sided drive as 2 separate single-sided ones), you cna damage the drive heads. Nothing woudl convince them that both heads touched the disk no batter which side was being used. I don't know if I was particularly unlucky, but I never had a single clueful maths, physics (or computing) teacher. I hope some other schools were better... -tony