FreHD or M3SE ?

[EtchedPixels]

I'm looking for something I can move easily between a gate array model 4 and a 4P in part to finish off getting the OS I am writing running nicely on real hardware not just the emulator.

The FreHD seems better documented at the low level and it's clear how to move disk images around and poke the hardware. It supports CP/M but if I read the documentation right needs an extra PCB for autobooting on the model 4 not just an EPROM change, and also seems to be want to be powered from the innards of the machine.

The M3SE has a lot more features but doesn't seem to have CP/M support out of the box (or does it just work in emulation anyway ?) but is a lot pricier and looks like I'd have to write all the tools to work with the raw disk images, it's a straight EPROM change and it looks like there are now power complications.

And neither of them (or maybe I need to look somewhere in the LSDOS information not the disk drivers ?) really document how partitioning of media works and how an OS is supposed to co-exist nicely with others.

There is just about enough low level documentation for the M3SE hardware, and rather more for the FreHD but then I don't expect nutter writing their own OS is the target market for either 8)

I'm mostly curious what the experience of people running things other than LSDOS is with the two options ?

Alan

 

[TRS-Ian]

Hi Alan, I recommend the FreHD but remember I am biased. Just avoid the fake ones out there.

On the 4GA you need either an adaptor board or replace U4 with a 28p Eprom and solder 4 wires. On the 4P you just replace the boot rom with a 24p Eprom and solder 1 wire. (On the Model III and 4NGA its easier, you just replace one 24p Eprom with a new one). FreHD can be powered from a wall-wart 5VDC supply but for neatness I prefer an internal power tap cable to power the FreHD.

The disk images supplied are partitions for optimal use of the system for the vast majority of users. Speaking of partitions, we are restricted by the design of the TRS-80 operating systems to 8 partitions, so on a dual drive Model 4 you have 4 hard drive partitions on LDOS and LS-DOS, 2 floppy partitions, and 2 "empty" partitions you can use to connect floppy images with DSK/DCT and a Memdisk if that is your desire. People have asked and eventually succeeded in creating their own hard disk images from scratch and if that floats your boat then its a bit of work and to a certain extent re-inventing the wheel as the existing images already work well.

On all TRS-80s FreHD is geared around LDOS/LS-DOS but also works with Newdos/80 2.5 on the Model III and MM CP/M is supported on the Model 4. CP/M works but the end user really needs to be a deft hand at CP/M as moving files between disks and the CP/M image can be complicated with the myriad of CP/M diskette formats out there.

In answer to your question "...how an OS is supposed to co-exist nicely with others?" the SD card holds a number of images, each are a single file, which is why they co-exist. When you press Reset it brings up a menu of all the images on the SD card and you just choose the one you wish to work with.

Hope this helps,

Ian.

 

[dittman]

[I see Ian responded while I was typing my answer so I've removed the redundant answers]

The FreHD works with Montezuma Micro CP/M 2.2 but not Radio Shack CP/M Plus, but the Radio Shack CP/M Plus is pretty limited so that's no surprise.

If you are writing your own OS either should work as you can write the drivers for it.

The partitioning will need to be handled by your driver by splitting the emulated hard drive into separate partitions.

Both the FreHD and M3SE emulate a Radio Shack hard drive with some extensions.

One thing on my project list is to add support for Radio Shack hard drives, FreHD, and M3SE to my CP/M Plus BIOS so I've started looking into the same issues.

 

[pski]

Of course I concur with everything Mav says about FreHD. FreHD is open source, runs many different OSes, mounts floppy images, etc. An awesome storage solution for the TRS-80.

But, if you are happy to stick in LDOS/LS-DOS land, the MISE/M3SE are hard to beat. The built in FTP is a killer app when managing and transferring files back and forth, say if you are doing software development like I do. And of course, you get all the other great stuff like the Ethernet (TRSWiki, TRS-Box , VGA, Joystick, etc.

Two outstanding products in the TRS-80 ecosystem, with some overlap, where both have their place and market segment.

 

[EtchedPixels]

I'm confused on one point - the 4P ROM contains code to boot from the tandy HD so does it need a ROM change for FreHD, or just to use the fancy boot menu stuff ?

 

[TRS-Ian]

The 4Ps ability to boot is restricted to Tandy HDs, but the FreHD dev team worked out a way to trick the 4P into auto booting LS-DOS or CP/M from the FreHD. Doesn't work with Newdos/80 or LDOS. Also, this way you are limited to one hard drive image per SD card. If you only work with one OS, say LS-DOS, then its the simplest way to go. The Rom change allows the menu and multiple images on the SD card.

 

[troj]

Late to the conversation, but I did a bit of reading on the options a while back and I've got a FreHD on order from Ian. Hopefully by the end of the month I'll be working on learning how to use one on both a Model 1 and a Model 4.

-Kevin