FreHD what is it?

 I stumbled across a FreHD on ebay. This is a bare bones board. You get the board, 50 pin cable for connecting to the TRS-80, and the SD card. No you don't get 32G of storage. You get plenty for the TRS-80 as this is a 40+ year old computer.

It is a TRS-80 hard drive emulator. It uses an SD card as storage and will emulate a hard drive and give you a Real Time Clock. It comes with all the software for you to use it. On the TRS-80 you get software to read from the main directory as a way to transfer TRS-80 programs from disk images which are prevalent under Windows.

Invented by Frédéric Vecoven in Belgium, the FreHD hard drive emulator enhances your TRS-80 with fast, unlimited, inexpensive storage on SD cards.  For insight into the design process of the fantastic FreHD, check out the inventors web site!

Since I have  a TRS-80 4P the rom has the ability to boot from a hard disk. This is as far as the TRS-80 is concerned a real hard drive. So I ordered one on ebay. 

I have a 3D printer so I have designed a simple case for it in Fusion 360. I also bought a 2A 5VDC power supply. A matching connecter, and a Push button switch with a blue led in it.

Here is a pic of Montezuma CP/M 2.2 booted up from FreHD

Here is the LS-DOS 6.3.1 booted up 

Upgrade from LDSOS 6.3.0 to 6.3.1L

 To get here

First off I found out all the source code for LSDOS 6.3.1L is available for download. It comes with a Z80 emulator so all you have to do is unpack the zip file and read how to compile LSDOS 6.3.1 from source.  Yes all the commented source is available online for this 30+ year old DOS.

The source is available from HERE. 

Once you have that you just unzip it.

You will find the file on how to build LSDOS 6.3.1L  called README.md in this directory \LSDOS631L-master

Basically you go to \LSDOS631L-master\LSDOS631L and run BUILD.BAT. This will start the emulator and mount all the images required to build LSDOS.

Once that is started in the emulator you type: do build (all,nostop

ALL is to build all the pieces

NOSTOP is so that it does not pause between sections.

This will start the process at speed not emulated speed so it will compile the entire DOS in about a minute. Yes the entire LSDOS will compile on my laptop in a minute. What is important to note is that this is just LSDOS. There is no basic with this as that was licensed from Microsoft and there is no source for for basic. 

The next post will cover how to get those files to an actual disk as after you complete the build the files are still only on a virtual disk. Not a real floppy disk.

Thanks for looking

Jim

First post

 Well I went and bought a 4p off ebay about a month ago. Way back this was my third computer I owned. My first being bought in 1980 a Model 1. I started out with that as a 16K cassette system when I was stationed at Fort Knox while serving in the Army. I expanded that with the 32k expansion interface with 4 floppy disk drives.

After that my second purchase was a Model 4 with 128K ram. I ran an old BBS system off that system for a few years. I upgraded that one to have have DSDD drives. So I went from 180K disks to 360k! That was huge back in the day.

Then one day I traded that system for a Model 4p with a friend who did not want to portable version he wanted a desktop. While I wanted the portable.  The only stipulation was that I would take out my upgraded drives and put back in my old drives and return it to stock. So I moved the DSDD drives to the 4P. This was a sweet system. It was about this time I shutdown my BBS and just was doing my computing thing. Back then if you had a computer and wanted to do something different you were also a programmer. My BBS software was written by myself all in Z80 assembler.

I did buy on closeout a 5 Meg hard drive for the 4p which was unbelievable storage for the 80's

Somewhere along the way the old 4mhz computer was abandoned and I went like everyone else into the IBM PC era.

But now I caught the nostalgic bug and after several attempts on ebay I won an auction for a reasonable amount. It came with a old floppy disk with LSDOS.  So that was a big score. People must have been sleeping as I was able to get this for the price of a turns on system. Which when they don't show this screen with the "The Floppy Disk Drive Is Not Available". I don't actually believe it turns on. Yes maybe the red light in the power switch comes on but that means nothing other then ac power is present.

So when this showed up it was  a good score. It booted the floppy but alas it was not LSDOS 6.3.1 Which can be patched to show up to year 2079. This was LSDOS 6.3.0 which the patch won't apply on, So the next time I will go over how I went to LSDOS 6.3.1 with the year patch. At least this will have a year I won't be able to outlive.

It is not in pristine condition what 35+ year old computer ever is. But it works and runs fine. Both drives can read/write/format floppies. I even found the compete source code online for LSDOS 6.3.1L and that includes everything to compile the source code under a z80 emulator. I will delve more into where I am today with this system in the next blog entry.

Thanks for following along as I explore this retro computing scene.

Jim