Probably the most sophisticated CP/M-80 machine ever made

[precaud]

The boot screen looks innocent enough, though that "g" in the BIOS version has special meaning...

[precaud]

Front and rear views suggest this isn't a typical Z80 machine.

[precaud]

And though you can run the generic CP/M software of the day on it, it was really built to do things like this.
1st pic is anechoic magnitude and phase vs frequency of a tweeter on a test baffle.
2nd pic is an 3D "waterfall" display (energy vs time vs frequency) of a speaker system.

[RoGeorge]

I'm intrigued by the Charge/Battery indicators, thought I see a power cord in the pics.

Is that portable, can it run on batteries only? 

[precaud]

So what is it, Johnnie?

It's a Tecron TEF-10 TDS Analyzer. A purpose-built Z-80 CP/M-based computer for doing acoustical measurements using Richard Heyser's Time Delay Spectrometry techniques. Inside are three Z80's, an AMD 9511 FPU, the usual 64kB of ram, sine and cosine oscillators, balanced mic and line-level preamps, etc. The "g" in the Bios string signifies support for the GPIB interface.

I bought this new in 1983. It has been in storage since 1989, when I upgraded to it's big brother TEF12+.

I set it up yesterday and it booted up. It ran all the software (from 38-yo 5.25" floppies) just fine. Time in a bottle.

I'm thinking of setting up a simple rig to measure headphones. My AKG C451E with CK2 capsule from the same period also appears to be just fine.

Fun stuff.

[precaud]

Yes, it can be powered from a 12V car battery. It has an internal NiCad pack that powers it for 10-12 minutes in the event of a power outage, giving you time to save your data and shut down gracefully.

[RoGeorge]

Wow, impressive!  Now I notice, indeed, that instead of ON/OFF the switch on the back reads DC/AC.

[precaud]

Yes, it's an impressive machine, the brain child of Crown's Gerald Stanley and his crew. Software was written in Kaypro's S-BASIC and assembler. Keith Jebelian did most of the OS and IO hardware code. Even with GPIB support added, it still had an impressive 57kB TPA!

[precaud]

The only thing that gives me the willies about using it now are the 720kB 5.25" floppies. I wish there was as SSD or flash replacement for 'em.

[Gyro]

The drives themselves are pretty bulletproof, or at least serviceable/repairable (much more so than 3 1/2"). You just need to stock up on media and make lots of copies!

[BrokenYugo]

The only thing that gives me the willies about using it now are the 720kB 5.25" floppies. I wish there was as SSD or flash replacement for 'em.

I thought that was an available product, "floppy emulator", pulls images off a USB drive and acts like a floppy drive on the other end.

[precaud]

You just need to stock up on media and make lots of copies!

Yeah, the media's the problem.

I thought that was an available product, "floppy emulator", pulls images off a USB drive and acts like a floppy drive on the other end.

The only ones I've seen are for 3.5", 1.44M PC format.

[gf]

Regarding emulator, the important question is, which hardware interface to the floppy drive is supported by the computer? I guess it is not yet ATA?

[precaud]

Definitely pre-ATA... I think most CP/M machines used a Shugart-standard interface, no?

[RoGeorge]

stock up on media and make lots of copies!

That's generally a good advice, yet I have 5.25'' floppy disks (same as old as from 1985) and still working OK (only rarely used).

For a backup, I've seen many projects for floppy disk unit (FDU) emulators based either on HDD, or on an SD card + microcontroller acting like a FDU.  The FDU interface stayed the same, so a whole unit can be replaced now with an emulator.

For a backup, either find an old PC motherboard and install an old Linux that can still read 720kB floppy disks, connect the CP/M unit to the IBM/PC and make a dd backup image of the entire disk(s) with the help of the PC.

If you don't find any, there was a tool named Kermit, for CP/M, tool that was able to exchange files over the RS232 port, or you can try to write one if the CP/M disks have some OS tools for a programming language.

Another option would be to search for existing backups on the Internet, maybe somebody else already copied the disks and uploaded them somewhere.  Last time I looked there were many places preserving CP/M software.

With the current PC speeds it would even be possible to record the row pulses at the output of the floppy head, the RDATA line. 

Also, there might be EPROM chips (UV erasable) that would worth a backup, too, but only if they are sitting on a socket.

[SiliconWizard]

Definitely pre-ATA... I think most CP/M machines used a Shugart-standard interface, no?

Yes.

[precaud]

... I have 5.25'' floppy disks (some as old as from 1985) and still working OK (only rarely used).

Same here. It is quite possible I am 'misoverestimating' (thank you GWB for bringing us that elegant piece of Amerenglish ) the potential unreliability of the floppy system. It never gave me problems.

For a backup, I've seen many projects for floppy disk unit (FDU) emulators...

For a backup, either find an old PC motherboard...

If you don't find any, there was a tool named Kermit, for CP/M...

Another option would be to search for existing backups on the Internet...

Thanks, but none of those things are necessary, I still have the master discs, and I can get files on or off the computer with ease by several means. It came with a utility that turns drive B into an MSDOS drive for read, write, even format.

Perhaps the best thing to do for now is to see how many good 2S2D disks I have, make working backups, and just use the thing. It's not like I'll be making hundreds or thousands of measurements. Dozens, maybe. I have several boxes of NOS 5.25" HD floppies but have already discovered they don't format well in DD drives. Something about write current being too low.

[RoGeorge]

1st pic is anechoic magnitude and phase vs frequency of a tweeter on a test baffle.
2nd pic is an 3D "waterfall" display (energy vs time vs frequency) of a speaker system.

No idea what methods are used to measure those in the audio industry, so the ways I'll try to measure such params would be one of these:
- either slowly sweep the frequency with a sinusoidal signal while continually measuring the amplitude and phase relative to the source signal (so analog phase and amplitude measurements logged while sweeping the frequency)
- or send a single square pulse, digitize the response waveform with an ADC, then turn the recorded time-domain response into a frequency-domain response with the help of Fourier

For either method, I think a single output signal should be enough, but I've seen on the back panel both sin and cos outputs, so I wonder why does the instrument needs both.

Do you have any hints how the instrument measures, please, or why does it has quadrature outputs? 

[PKTKS]

The only thing that gives me the willies about using it now are the 720kB 5.25" floppies. I wish there was as SSD or flash replacement for 'em.

It is possible...  I have seen some folks adapting an interface for SD-CARDS
using a custom based I/O attachment fixture... even possible it they (already have)
are also capable to offer S-100 (Altair 8800)....

Although I have seen this for sale  for PCs the Z80 I/O is very close to 8085/8080 if not identical in this particular case..  someone with will and time should be able to interface a Z80...

Those graphics written in Assembly are a work of art..

Paul

[precaud]

No idea what methods are used to measure those in the audio industry, so the ways I'll try to measure such params would be one of these:
- either slowly sweep the frequency with a sinusoidal signal while continually measuring the amplitude and phase relative to the source signal (so analog phase and amplitude measurements logged while sweeping the frequency)
- or send a single square pulse, digitize the response waveform with an ADC, then turn the recorded time-domain response into a frequency-domain response with the help of Fourier

For either method, I think a single output signal should be enough, but I've seen on the back panel both sin and cos outputs, so I wonder why does the instrument needs both.

Do you have any hints how the instrument measures, please, or why does it has quadrature outputs?

Personally, for speakers and acoustics, I never had a need for the quadrature output. My guess is it was provided for completeness. The digital version of the signal is used for computation internally.

In simplest terms, TDS is a swept sinewave with a phaselocked swept bandpass receiver with programmable bandwidth and delay. Removing the airpath delay allows it to measure absolute phase. And at a given sweep rate, varying the bandwidth of the receiver IF controls the "time window" of the measurements; narrower makes then anechoic, wider to include room reflections. With a directional microphone, you can isolate and measure the spectra of individual reflections to the complete exclusion of the direct signal. Or absorption coefficients of materials placed over the reflected surfaces. All this with the the huge SNR advantage that swept measurements give over FFT-based impulse or chirp techniques. And there's a whole time domain aspect to it as well; an FFT of the IF signal yields the energy density vs time.

The best thing to do is to read up on the basics of TDS. Google "Time Delay Spectrometry" and you'll find plenty of material. Heyser's AES papers are highly recommended.

[precaud]

It is possible...  I have seen some folks adapting an interface for SD-CARDS
using a custom based I/O attachment fixture... even possible it they (already have)
are also capable to offer S-100 (Altair 8800)....

Although I have seen this for sale  for PCs the Z80 I/O is very close to 8085/8080 if not identical in this particular case..  someone with will and time should be able to interface a Z80...

Will and time, that is the key...

Those graphics written in Assembly are a work of art..

Totally agree!

[PKTKS]

It is possible...  I have seen some folks adapting an interface for SD-CARDS
using a custom based I/O attachment fixture... even possible it they (already have)
are also capable to offer S-100 (Altair 8800)....

Although I have seen this for sale  for PCs the Z80 I/O is very close to 8085/8080 if not identical in this particular case..  someone with will and time should be able to interface a Z80...

Will and time, that is the key...

But even putting the fixture in place...

The CP/M kernel was never meant to use any other DEVICE than those at default installation...

Finding a suitable format  on an alien DEVICE like an SD-CARD will certainly be a problem...

Paul

[precaud]

That is my sense of it as well. A BIOS rewrite would be required.

[jmelson]

The only thing that gives me the willies about using it now are the 720kB 5.25" floppies. I wish there was as SSD or flash replacement for 'em.

I have a Pick and Place machine that runs Windows 95, and used a 3.25" floppy for data exchange.  I got a device mostly sold for use with music synthesizers that makes a USB memory stick (thumb drive) look like a bunch of 1.44 MB floppies.  I'm not sure that would work for your 720KB disks, but maybe somebody makes one of these that will do 720K.  What I have is the Gotek-SFR1M44-U100.

Jon

[precaud]

I have a Pick and Place machine that runs Windows 95, and used a 3.25" floppy for data exchange.  I got a device mostly sold for use with music synthesizers that makes a USB memory stick (thumb drive) look like a bunch of 1.44 MB floppies.  I'm not sure that would work for your 720KB disks, but maybe somebody makes one of these that will do 720K.  What I have is the Gotek-SFR1M44-U100.

If the interface was the same, that could be an option. This https://www.vcfed.org/forum/forum/genres/other/65362-identifying-shugart-interface-5-25-floppy-drives?p=794197#post794197 discussion on vcfed.org suggests it's the same at the drive end but not at the controller end. They're different connectors at the drive end, elso, though I seem to recall seeing adapters. It's been a long time since I last futzed with this stuff.