System MK3000

In another part of the site where I discussed the research done on the history of Italian Ferguson Bigboard card I had given some information about the system MK3000 produced in Italy since 1983 by the ADE Electronics Palazzolo Milanese (Milan). In December 2012 I managed to get hold of this system. It 'consists of a board with MK83 processor Z80A two Z80A PIO (for dual port printer, mapping i / o port keyboard, a Z80A SIO / 0 for two-channel RS232, one Z80A CTC system timer and an FDC 1797 management FM / MFM drives. The board has two 50-pin IDC connector for drive 8 "drive and IDC 34-pin 5.25". The drives are present:
- Floppy disk 5.25 "BASF AG 6106 (180 Kb, SS / DD)
- Floppy disk 5.25 "Shugart SA465 (720 KB DS / DD)
Unfortunately, the hardware was not completed with the respective software CP / M, even if the conditions are really excellent visual hardware.

DSCN0020

The Ing. Lucky Luciano at that time (1983) worked at the CNR in Pisa ended with a commitment to long-standing problem of data entry on the IBM 370 mainframe in use at the time CNUCE. If it was necessary to punch cards and then read them to a machine to launch their own programs, now it was enough to bring floppy disks 5.25 "disk in any format readable by the operating system CP / M. In fact, he bought a card configured to read in either mode DSDD that SSSD and any format bytes / sector, and sectors / track can transfer protocol through the BSC program to do, turn on the mainframe. Here is a page that describes the system extracted from the manual which I managed to get hold of the site CNR - ISTI in Pisa:

MK3000

The above seems to be a truism today, but I remember that in 1983 this simple operation entailed enormous losses of time unlike today where this can be done either locally or on its systems that may be with any smartphone or tablet in the cloud.

Unfortunately, the system was not complete boot disk for your operating system CP / M and its utility, so after you connect to the card using a PS2 keyboard PS2-Parallel interface, you connect a TV monitor with PAL analog composite input, the power supply, with an ATX power supply I proceeded to turn on the card being able to get the clear initial screen, the message "System Monitor 4.2" and the prompt "m>". There were also many other operating firmware commands as the memory dump, etc.. So I made ​​some more tests to see how being able to put it in terms of loading an operating system CP / M.

I was not certain, however, that by directly connecting the 3.5 "drives directly to 34-pin IDC connector from the card MK83, they could function properly. At the very least there would be change from the normal setting DS1 DS0, but my experiences tell me that the connector of a 3.5 "drive is not immediately compatible with the connector of a drive 5.25". To avoid dedicate to solve this problem, I decided to skip taking care to disconnect a drive adapter that I had homemade in January 2012 and it is working perfectly with my MK82 whose schema is as follows:

DriveBus

In it, the 50-pin IDC connector is directly connected to the IDC connector to 50 pin connector on the board MK82, while the connectors A, B and C are normal IDC 34-pin on which you can insert a classic flat cable for drive 3 5 "or 5.25". D connector, you can connect a flat cable to connect an external drive 8 ". The main motivation to achieve a connection of this type is inherent in the fact that the 3.5 "drives are not directly interfaced sull'IDC the MK82 for the management of the Ready signal, because each drive expects the Drive Select signal on its pin 12 while the MK83 the sngoli signals are attested on different pin IDC connector to 50-pin (A = 26, B = 28, C = 30 and D = 32).

With this in mind I spent trying to figure out how to load an operating system CP / M.

There is to say that the content of the EPROM (2716) of the MK83, as for the card Ferguson Bigboard 1 (= MK82), is, at the time of ignition, automatically copied to DRAM, but while in Ferguson Bigboard 1 (or MK82) is placed at F000H, F800H in the MK83 is positioned at. Therefore it is not possible to load the card MK83 the same operating system CP / M MK82.

I have, however, pointed out that, c bout a year ago, I had the opportunity to be contacted by a person of Modena which had an identical card MK83 used to manage his knitting machine. Looking at the pictures you sent me, I noticed the same hardware configuration part of the FDC with the one in my MK83 WD1797 FDC consists of a separator and an external data FDC9229BT.

I then proceeded to:

1) Install the EPROM (2716) with the BIOS of my in my MK82 MK83: MK83 made ​​my BOOT properly operating system CP / M card MK82.

2) program, a new eprom 2716, the contents of the firmware for the MK83 given me by the person at the time of Modena, to install it on my MK83 and groped to make the loading of ITS CP / M: this has allowed us to develop the My MK83 operating system CP / M for MK83.

Waiting to recover a pair of drive 5.25 "working with the same characteristics for the system MK3000 and who knows, maybe even its operating system CP / M original, I shall properly interface with a pair of 3.5" drives with MK83 firmware and operating system CP / M MK83.

I have my card with MK82 z80 2.5 MHz and FDC 1771. Upload F000H in the bios and booting CP / M from floppy disk size 8 "x 128byte sectors SSSD 26 track 77 track single sided single density.

I took a card with MK83 Z80 B and FDC 1797. Upload your Bios to F800H but I have floppy system.

If you try to read a diskette with the command MK82 r0, r0, and then 0.1, 2.1 I see a video that correctly reads the sectors.

If I take the bios of the MK82 and MK83 do I put it in the boot with the disks of the MK82. If I try to boot with the bios loaded F800H fails because the disk system is configured to "find" entry points to F000H.

I remembered that Fabio Marverti of Modena had a MK83 (I call MK83F) that loaded the bios and had a F800H system disk double-sided double-density or rather, the first two tracks double sided contains the cp / m in size 26 sectors of 128 bytes . The subsequent 75 are composed of eight sectors from 1024KB in double density on both faces. With this in mind, I did send the card.

If I program the EPROM with their respective bios and exchange them none of the board gives me the system prompt. But they continue to charge their bios to F800H.

On my MK83 I can read a disk sector by sector manually sssd 26 128byte sectors.

If I try to read the disk system MK83 fabio Marverti I can read sisetma sectors that are still in sssd side0 side is that side side 1, but if I try to read from track 2 onwards (in which sectors are in 8x1024byte DD) do not read them.

I finally thought that if my MK83 able to read a diskette is in SD if I could copy sysgen with the cp / m fabio (ie, the first 2 tracks on the disc) on a single-sided disc in SSSD, but this way I'm missing But the part of the operating system recorded on the hard side 2 side fabio.

I do not have the most 'clue how to create a new disk CP / M.

Finally: I managed to copy and sysgen init on system disk fabio, these being generated by a disc of the Mk82 SSSD will not work.

Summary:

The card is clocked at 4MHz and Chip Series Z80B, a memory chip of 32 × 4116 (= 64 Kbytes), a BIOS EPROM 2 content in 2716 to 200ns, and an FDC 1797 FDC9229BT external data separator. The bios is loaded into RAM at the address F800H and I do not have the relevant records of the operating system CP / M. By inserting the eprom of my MK82 instead of his bios (this is loaded into RAM all'idirizzo F000H), the card performs properly boot from the disks of the MK82 (SSSD 26sect x 77 track single sided single density).

Fabio Marverti Modena contacted me because they possessed a very similar card, sent me his card that is clocked at 4MHz and Chip Series Z80B, a memory of 8 × 4164 chip (= 64 Kbytes), a BIOS contained in 1 2732 EPROM from 200ns, and an FDC 1797 FDC9229BT external data separator. The bios is loaded into RAM at the address F800H completely fitted the relevant records of the operating system CP / M (DSDD sect 8 x 75 track double-sided double-density 1.2 MB).

The idea was: if the cards "look alike" I could copy the BIOS in my Fabio to use his records to ssitema and have a complete machine operating system?

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