Least PC-Compatible MS-DOS machines?

How about the east german Robotron A7150 aka CM1910? That machine has am Siemens-AMS Bus compatible Card Cage (Multibus I) called MMS16 using DIN41462 connectors and two Z80A Based Subsystems, one for the Floppy and Winchester Disk, the other one for the (color)graphics using an uPD7220. The bus is multimaster capable and there are even dual port RAM Cards for use with multible CPU Cards. There is one connector for the system bus and another one for the local Z80 Busses for the two subsystems. The Keyboard is connecetd serial using 20mA Teletype interface and has a Mode for CP/M86 that will pu out ASCII Characters and an additional mode where is delivers Scan codes. The CPU is an I8086 (or russian K1810WM86) and mostly there is a 8087 on a doughterboard installed. The DMA is an 8257, the Centronics Interface is using an 8255 and serial is an 8251 on the CPU board but there are Z80 SIOs on other Boards too (ASP). Clock is 4.9Mhz. It is a bit slower than a average XT because of the multimaster bus arbitation. Besides of programs using the serial interfaces, most other DOS things will work unsing a double scan CGA Mode. There are SCP (CP/M86), Mutos (some Unix) and BROS 1810 (IRTS?) Os'es available too. DOS was Called DCP on that machine (Disk Control Program) The MMS16 Bus was first developed for use in machine controls, there where Z8000 CPU Cards for that Bus too.... http://de.wikipedia.org/wiki/A_7150 http://www.robotrontechnik.de/index.htm?/html/computer/a7150.htm CPU: http://img-fotki.yandex.ru/get/5635/119497768.1/0_9e411_2106ad6a_XL Here are more pictures from the internals: http://habrahabr.ru/post/162043/ (russian site) The computer had two names, A7150 in the GDR and then it was listed in the eastern countries SKR Standard System as CM1910 where CM are cyrillic letters, so it is pronounced SM1910.. Regards, Holm -- Technik Service u. Handel Tiffe, www.tsht.de, Holm Tiffe, Freiberger Stra?e 42, 09600 Obersch?na, USt-Id: DE253710583 www.tsht.de, info at tsht.de, Fax +49 3731 74200, Mobil: 0172 8790 741