Category: STD Bus

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Machines that are built around the STD industrial bus.

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Pulsar 9000 Solid State Drive Arrangement

Posted on by Graham

A gotek is a more convenient and reliable option for loading programs from disk images than actual disks. I just load the HFE files onto a USB stick for the gotek and then use with a 50 pin to 34 pin adapter to connect.

A gotek will never match an 8″ drive for beauty!

Where required and possible, the terminal option has been configured for Televideo 925.   

DiskE:F:G:H:
Capacity16MB16MB16MB25MB
User    
016 bit TurboDOS Files   Wordstar8 bit TurboDOS Files   Wordstar8 bit TurboDOS Files   Wordstar8 bit TurboDOS Files   Wordstar
116 bit TurboDOS Files BackupPascal MT/Plus Sources Development (048)   Pascal MT/Plus V5.5 & Programs (047/044)Pascal MT/Plus V5.5 Support Files Development (48)Pascal MT/Plus V5.5 G. Purpose Development (49)
2Wordstar/ Turbo Pascal (260:1)Wordstar/  Pulsar CP/M 2.2 128B/sec
Basic Electronics Programmes (42/39)		Turbo Pascal (054/051)
3Digital Research 16 bit tools (231)Pulsar CP/M 2.2
General Purpose Utilities Development (58/55)		Multiplan (118/101)Zork (440/318)
4 Dbase (59/56)Pulsar CP/M 2.2
PLI-80 Programs (65/62)  		SS/SD 128B
Versafloppy II
Cobol Compiler
Master Copy (223/163)
5 Supercalc (332/248)Cross Assemblers (008/007)CP/M 2.2 128B/Sec
Vedit Original Master (CP/M 2.2) (236/168)
6 MBasic Games (066/063)  MBasic & Basic Compiler (240/171)CP/MUG Vol 53 (Adventure & Mbasic Games) (088/77)
7  JRT Pascal V3.0 (261/189)     Looks like it wants to run off floppies. 
8  Diagnostics II (262/190) 
9 Fortran (57/54)  

The first number is disk id of the source image. The second number is gotek disk number of the source image.

There seem to be bugs in some commands (eg DIR) when the user number hits double figures – this seems to be just with the hard disk.

Pulsar 9000 A Real Hard Disk

Posted on by Graham

There are two hard disks that came with the rest of the items. One was in the drive rack and the other was stored separately. The latter was clearly marked as being TurboDOS for the 80186.

DriveLabelCapacityConfigurationSpeedStatus
Miniscribe 8425?TurboDOS 8018621MB4 Heads 615 Cylinders 17 Sectors/Track  68msBoots 7 bad sectors marked
CMS Enhancements (Kalok) KL 320 Octagon 21MB4 Heads 615 Cylinders 17 Sectors/Track  48msUntested

At least superficially, these drives appear compatible.  Neither are listed in the TurboDOS 1.4 configuration options, but there is an option for a Miniscribe with similar parameters.

Both of the disks have MFM/ST-506 interfaces.  The Pulsar 6216 has a SASI/SCSI interface.  An Adaptec 4000 adapter board converts the drives to SCSI.  The configuration program is aware of the adapter.

It was a bit of a surprise to see the machine boot from the miniscribe hard drive, as it probably hasn’t been powered for about 35 years.

It booted up to a user prompt. I was able to guess a user (accounts). It had no password, but was not privileged. It threw a few bad sector errors.

I found a post that said that TurboDOS stores its user ids and passwords in userid.sys on user 31. Unfortunately, 31 cannot be accessed without being a privileged user.  Fortunately, there were some backups on floppy disk. 

I booted up with floppy disk and then changed hard disks and copied the userid.sys file to my solid state drive. I could then have a peek:

Then I changed back to the old hard drive and was able to login as system.

Once there, Verify was used to check for and mark bad sectors:

Stat returned:

This system has disabled all floppy disk drives except A. There are two partitions on the hard disk B: and C:.

The baud rates are set to 19200 with 7,1,E.

There are 4 Z80 slaves.

There’s a fair chance that the hard disk will die. Often they power up ok to fail in the next month or so.

I tried copying the boot tracks using Boot, but the SCSI2SD drive will still not boot.  There must be a trick.

Using HD 5.25″ FDDs as 8″ Drive Substitutes

Posted on by Graham

High density 5.25″ disks have much the same capacity as 8″ double density disks, and they operate at the same data rate. A 5.25″ FDD typically has a few more tracks than an 8″ FDD.

This means that a floppy disk controller expecting to see an 8″ disk drive can potentially be fooled into working with an HD 5.25″ drive. This can be very handy if you don’t have an 8″ drive or if you want a more compact setup. This trick seems to work ok with a real HD drive or with a gotek/flashfloppy. 8″ disk images can be written to HD 5.25″ media without alteration using Greaseweazle, for example.

There are a few small issues. The first is the 8″ drive interface is usually 50 pins and the 5.25″ interface is usually 34 pins. The disk controller may have both interfaces (eg the Jade DD and the 16FDC) but not always (eg the Pulsar Little Big Board only has a 50 pin interface). If there is no 34 pin interface, then an adapter will be required. The 50 pin interfaces vary a bit, so a specific adapter may be required.

The second is that 8″ drives can detect whether a drive is single or double-sided and tell the host. The operating system driver may exploit this information (eg Jade DD CP/M) so there may need to be a way to fake this. For systems that use only single sided or only double-sided disks the signal can be tied appropriately otherwise a switch may be required – and if there are different drives in the system then it may be necessary to take the signal low through a diode from the drive select line.

Third is that 8″ drives typically produced a ready (RDY) signal. Without this signal, a host may just hang. This signal is available on many drives and can usually be setup on a gotek/flashfloppy but it may not be connected on the 34 pin interface. This can be overcome by connecting pin 34 on the 34 pin interface to the appropriate pin on the 50 pin interface.

Little Big Board Computer

Posted on by Graham

This was a home build based on the Pulsar Little Big Board. The machine came with an open rack with two 8″ floppy disk drives and some scary looking power supply wiring. It runs CP/M or TurboDOS.

The mains wiring and chassis earthing has been brought to a level where it no longer strikes fear. The chassis has been enclosed in clear perspex so that the authentic bespoke build and striking 8″ floppy disk drives can be enjoyed.

The drives are Y-E Data YD-180.

The Little Big Board design is well known in Australia, having been published in Electronics Today International.

Pro-Log System 20

Posted on by Graham

Pro-Log was a major manufacturer of STD cards. The cards here arrived in a collection of almost 100 STD cards (thanks yet again, Andrew). I guessed by their appearance and dates that they probably went together, and later found that they were all related to a Pro-Log System 20.

The card cage is not the original unit but works fine. The system boots a ROM version of MS-DOS 3.2. The ROM card also has 128k of RAM for a RAM disk with provision for battery backup.

The 8088 processor card has 128k and with two additional 256k RAM cards the total system memory is 640k.

The system also includes a CGA card, floppy disk controller card, printer card, and a prototyping card.