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Category: Retro computing

DREM – MFM/RLL hard drive and Floppy emulators

DREM – MFM/RLL hard drive and Floppy emulators

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Connecting old floppy disk drives to modern hardware is not easy. Resurrecting old MFM and RLL hard drives is even harder. The primary method would simply be to get an old PC with the legacy hardware to read the hard drives. But now there’s a few soltuions.

DREM:

DREM is based on the high performance FPGA platform and does not require the use of a PC for any file encoding operations. DREM is equipped with an VGA output, PS/2 keyboard input and file manager software. A user can browse the SD card and insert DSK images into virtual drives.

DREM uses DSK disk image files, which contain the raw dump of a disk. The raw image consists of a sector-by-sector binary copy of the source medium.

If you’re just looking for floppy emulation, I recommend GreaseWeazle or other solutions.

https://www.drem.info/drem

MFM Board Emulator:

Also available, but doesn’t seem quite as well baked, is the pdp8online MFM board emulator.

Early AI was more like a therapist

Early AI was more like a therapist

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ELIZA was an early ‘AI’ created by MIT scientist Joseph Weizenbaum between 1964 to 1967.

He created it to explore communication between humans and machines. ELIZA simulated conversation by using very simple pattern matching and substitution that gave users an illusion of understanding – but it had no representation that could be considered really understanding what was being said by either party. Something you can easily discover by playing with it for a few minutes.

Fast forward to 1991, and Creative Labs was having amazing success with their SoundBlaster add-on sound cards. On the driver disks that came with the SoundBlaster, there were programs showing off different capabilities. One of these capabilities was voice generation. To show off the ability to voice synthesize text, Creative Labs included a little program called Dr. Sbaitso (SoundBlaster Acting Intelligent Text-to-Speech Operator).

You interacted with it like a pseudo-therapist; but you can clearly see the connections and similar pattern/substitution methods that Eliza used. I remember being wowed by it when I played with it for the first time – and experimented for hours with it. It quickly shows its limitations, but the speech synthesis was very good for the time.

It doesn’t hold the test of time, but it is pretty neat and you can even check it out here:

https://classicreload.com/dr-sbaitso.html#

ISA over USB

ISA over USB

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Plugging in old ISA cards is something that hasn’t really been possible since 80486 days. This makes plugging in cool things like Sound Blaster, Adlib, Monster3D and other ISA cards pretty much impossible for modern computers. It also means things like attaching 5.25″ floppy drives and old MFM/RLL drives are also off the table. Well, maybe. 🙂

There have been a few efforts to enabling plugging in ISA boards to modern pc.

  • dISAppointment that I wrote about before is a USB plugin that exposes an ISA interface.
ISA buses on a modern PC?

ISA buses on a modern PC?

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Welcome to dISAppointment! Well, it has been disappointment for anyone wanting to use old retro sound cards or attach 5.25″ floppy drives or MFM/RLL hard drives in modern computers. They all relied on ISA controllers, which have not been supported for over a decade now. But is that about to change?

I recently read about this really clever hacker’s adapter.  TheRasteri found he could still access the ISA bus lurking latently in modern computers through the Low Pin Count (LPC) bus which is exposed on the TPM port in many modern motherboards. He created a hardware interface board that connects to the TPM port, exposes an actual ISA slot.

He plugged in a Sound Blaster card via the adapter – and voila! It worked.

More details on his YouTube site, or you can follow the active development thread on Vogons. No word yet if he’s producing any for purchase; but he does want to open source the work and wants to see if he can partner with PCBWay to develop them.

I for one would absolutely buy a few of them.

Update:

Fintek makes the F85526 PCI Express to ISA Bridge IC.

  • PCI Express base spec 1.1 compliant
  • Fully ISA bridge support except bus master

It seems promising, but it is unclear if anyone has built a functioning device around the chip. Vogons even discussed it on their thread that also mentioned the dISAppointement ISA device.

New Old Sound cards

New Old Sound cards

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Retro gaming has a solid community – even in the PC world. Prices of old hardware keeps going up as supply of working components goes down as time goes on. But would you be surprised to hear that people are out there making new components for these old machines? I already mentioned the recreated Covox Speech Thing, but there are even re-creations of Adlib, SoundBlaster, and other early sound cards. Enter the Orpheus ISA 16 sound card that can emulate just about any 90’s era sound card perfectly.

Dreamblaster available for purchase here: https://www.serdashop.com/RetroSoundcards

Update: There’s other makers of clone cards too:

IBM PC Convertible

IBM PC Convertible

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My very first computer was a TSR-80. I learned to first code out of necessity – you had to type in all the programs you wanted to play. My dad then purchased one of these wonderful beauties: The IBM PC 5140 Convertible.

Art Institute of Chicago

The computer was a miniaturized IBM XT 8088 system with only 2 floppy drives and no hard drive. Still, it was a huge step up with the ability to save and load programs from floppy disks.

I love that people try to preserve the history of these wonderful old machines – and you can find everything about the system including original boot disks, specs, and configurations. There also appear to be copies of the original boot disk and ROM set that work on MAME.

Parallel Sound from the Past

Parallel Sound from the Past

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Back in the 90’s, computer audio devices were really limited. If you were relatively rich, you could afford a $150 Sound Blaster, or maybe a $75 Adlib. If not, you were limited to the very humble PC speaker. It turns out, however, there was one other option that didn’t get a lot of visibility.

The Covox Speech Thing (and a similar device called the Disney Sound Source) was an external audio device attached to the printer port and could output digitally generated sound. The device was a criminally simple 8-bit DAC created with a resistor ladder, an analogue output plug, and ran off simple digital signals from the printer port of the PC. How simple was it? So simple you can easily make it yourself.

Necroware does a great job covering the device, how to make your own, and gives you a full tour of the device as well as 90’s software you can use with it. Most notably, Tracker software which gave me tons of fond memories.

Update 02/2024:

Serdashop has the Covox compatible CVX4 Vogons Tuning Edition for €20. Now on it’s 4th and final version – CVX4 uses very high precision 0.1% all same value resistors, and a reverse engineered schematic (based on a real original covox). Other DIY clones use 1% or 5% resistors. Probably one of the best versions out there.

Links:

8″ Floppy drive

8″ Floppy drive

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8″ floppy drives are the earliest form of floppy drives connected to early minicomputers. By the time of personal computers, 8″ floppy drives had been replaced with 5.25″ floppy drives. But those 5.25″ (and later drives) were still often based on the Shugard interface.
Adrian’s Digital Basement shows how he hooked up an 8″ floppy drive from a TSR-80 Model II to a 386SX computer – and gets it to boot! This is almost certainly something I want to try some day.

Link:

Reading 3.5″, 5.25″, and 8″ floppy disks with Raspberry Pi

Reading 3.5″, 5.25″, and 8″ floppy disks with Raspberry Pi

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It looks like people have been using Raspberry Pi’s to connect and read floppy disks. Below are some of the links. Note that it appears they are only reading data, not writing. See my other posts for both reading and writing to 5.25″ and other floppy drive interfaces.

Links:

GreaseWeazle

GreaseWeazle

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Have you wanted to read and write data off your old 5.25″ floppy disks with a modern computer? Or how about reading/writing floppies for Apple II, Amiga, ST, or a host of other systems? Or maybe even hooking up a 8″ floppy? It is possible!

There are solutions out there, but they can easily run $100 or more. I, however, picked up the GreaseWeazle and read some of my old 5.25″ disks. Best yet, it only cost $31 Canadian and is one of the more capable solutions. You can supposedly even use your old DOS floppy drive to read/write images for other platforms.
If you’re interested in seeing it at work on some unusual formats, this fellow gives a walkthrough of using Greaseweazle to read 3″ Amstrad disks. Pretty darn cool.

Items you’ll need:

  • GreaseWeazle by Decromancer – the plug-in USB board that makes it all possible. Plug in 3.5″, 5.25″ and 8″ drives and read/write the flux data for hordes of different formats.
  • Floppy drive – any 5.25″, 3.5″ or 8″ floppy that uses the Shugart interface. This is almost all old PC drives. Even better, GreaseWeazle can use these older DOS drives to read and write Apple, Amiga, ST, and a host of other formats.
  • Floppy disk cable – CablesOnline (ebay store) has a universal floppy cable Item # FF-002 for $9.99
  • Power supply with Molex connectors for the floppy drive. Either using a PC power supply with a Molex connector, or a stand-alone power supply with Molex connector
  • USB A to B cable (commonly known as a “USB printer cable”) to connect the GreaseWeazle to your PC

Setup:

Your floppy drive won’t show up in a command prompt like they did back in the old DOS days or like modern USB plug-in 3.5″ drives. Instead, you have to load and write whole images to the drive in one go. This means you need to work with floppy disk images.

  1. Set up your physical floppy drive to be used with GreaseWeazle.
    1. Attach the power cable to a power supply
    2. Attach the data cable to the floppy drive and the GreaseWeazle
  2. Follow the instructions on GreaseWeazle setup and software setup guide.
  3. Plug in the GreaseWeazle to your computer’s USB port
  4. Install and run GreaseWeazle GUI to format a disk, read a disk image, write a disk image, etc. Again, this only works on whole disk images. You can’t browse at a command prompt or read/write individual files/directories.

Optional but helpful tools:

  1. WinImage is a great tool for creating and converting disk image formats.
  2. Use the HxCFloppyEmulator to examine and covert the raw disk images to anything you need.

Learn more:

Tech Tangents talks about how preservationists use tools like GreaseWeasle to back up disks.

Resource Links: