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making a Trs-80 model 1 level 2 boot disk

Are you sure the expansion interface is single density? If so, it's great that you could write out a disk from an image. On most PCs this is very difficult. Well done.

Tez
 
I got it working without the AHA.The 5 1/4 floppy is plugged into the PC motherboard floppy controller but I can only write TRS-80 disks in dos but that's no problem.
 
Lurch666 said:
I got it working without the AHA.The 5 1/4 floppy is plugged into the PC motherboard floppy controller but I can only write TRS-80 disks in dos but that's no problem.
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Cool. But are you SURE your expansion unit in the TRS-80 has not been upgraded to double density (many were), and the TRS-80 boot disks are not double density. If they are indeed single density, can you let me know the type of motherboard. Some motherboard disk controllers can write single density apparently but they are rare. It would be good to know what types do.

Tez
 
Sorry I misunderstood.How can I tell the difference if my E.I. has had a double density upgrade?

The motherboard was a A-Trend ATA-V931-CX0 SKT 370 SKT1 VIA Pro133.
 
Lurch666 said:
Sorry I misunderstood.How can I tell the difference if my E.I. has had a double density upgrade
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Hmm...good question. I don't have a double density upgrade myself but I THINK it's a very small daughter board plugged into the floppy disk controller socket. You could also format a floppy disk and see how much space you get on the blank newly formatted disk. If it's double density it would be 2x more than single density.

Assume your LDOS just formats ONE side of the disk (I think this is the norm but I'm far more familiar with NEWDOS that LDOS) AND it's a 40 track drive then single density should give you about 80k or so. If it's double density it will be 180k or so.

As I say I'm not that familiar with LDOS. If it somehow detects that you have a double sided drive it might even format both sides of the drive. In which case even single density will be about 180k. Double density would be about 360k.

I'd be interested to know what you find.

Tez
 
I've just done a DIR on my TRS-80 and it says 87.5 free.Dunno if this is k or not.I figure it's only formatting one side as the disk only had the one notch cut in the side for writing.
 
Is that a blank disk, or one with LDOS on it? If it's a blank disk, then I would conclude that you do indeed have single density. If it has LDOS on it, well that OS takes up a spare amount of space anyway and it may be double density.

You don't need two notches on the disk for the machine to use and write on both sides of the disk. A double sided disk drive needs only one notch. The only reason you'd need a second notch is if you had a single sided drive and you wanted to flip the disk to use the other side.

Tez
 
Lurch666 said:
Well it was a disk full of files so it actually said FREE=0/87.5 but I remembered after it was formatted it said FREE=87.5/0....
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Hmm...jury is still out in my mind. If it was full of files and reported 87.5 free it may be double density. Only a completely blank disk with no files at all on it would report 80k or so free space.

When you say "after it was formatted" are you talking about after the image was written on the PC, or a disk formatted by LDOS on the TRS-80 itself?

Double density was an optional extra but a lot of second-hand units on the market today do have the mod fitted.

Tez
 
I'm interested in this because being able to format a single density TRS-80 disk on a PC without special hardware is very rare, whereas double density is no problem.

I just tried Model 1 LDOS in Matthew Reed's emulator. I used a single density boot disk image but had the doubler enabled. It booted the disk fine as expected, as I'm sure a machine with a doubler can boot single density disks. Formatting a disk (single sided) in virtual drive 1 though, only gave me 100k or so free...which is about what you'd get for a single density, 40 track disk. This is surprising. Why it didn't format in double density I don't know? Maybe if you boot from a single density disk, it assumes all disks are single density by default and you need to tell it somehow that double density is possible?

I need to swat up more about LDOS.

Anyway, don't worry about it. I'm just curious. If you ever do manage to get the top off your expansion unit I'd be interested to know if a doubler is there (or not).

Tez
 
LDOS double density formatting:

1. FDUBL(percom) - two choices, percom and tandy. I assume there are more percom doublers than tandys
2. FORMAT :z (SYSTEM) - z=drive number as appropriate (but you knew that) [colon+x = a "cross" (angry) face emoticon on this site]
3. Select D)ouble density
4. Choose sides and cylinders as appropriate.
When it starts verifying the format, you'll immediately know if you formatted double density. However, if you don't succeed the first time, reboot and follow the above but just FDUBL - tandy is default and not needed.

Single side, double density, 35 track yields 180k disk space
SS DD, 40 track yields 200k
Double side, DD, 40 track yields 360k

I have had very bad luck using Matthew Reed's Model I DOS emulator, but "Your Mileage May Vary"

Mike
 
Thanks Mike,

I've been looking at the LDOS manual and saw those choices too. I tried them before reading your post here.

I can't seem to get Matthew Reed's TRS32 emulator to format a double density disk from a single density LDOS system disk. Despite using all the (apparently) correct syntax i.e. (Q), (QUERY), and your (SYSTEM) I just never get the prompt allowing me to select the density. It just defaults to single density,even when Percom, Tandy or Both doublers are selected. Odd.

The command FDUBL comes up with a program not found on my LDOS 5.1.3 and 5.3.1

Tez

Anyway, thanks for publishing the free space on a typical blank double density disk.
 
FDUBL was known as RDUBL (for Radio Shack doublers) and PDUBL (for Percom or any other brand doubler) on versions prior to LDOS 5.3.0

Roy then decided to combine the two into one program. FDUBL<Enter> invokes double density driver for Radio Shack doublers and FDUBL (PERCOM)<Enter> invokes the double density driver for all other brands of doubler.

Ian.
 
When I said about the free space on a my disks it displayed FREE=87.5/0 after a format (blank disk) and FREE=0/87.5 after I filled the disk where I assume FREE shows [the amount free]/[amount used].

From the comments here it looks like it is single density but to confirm when I get back from work I'll open my E.I.
 
Lurch, your EI is standard single density.

What we found early on was that you could format a diskette on most single density systems with more than 35 tracks (basically only Shugart SA-400 disk drives can do 35, but most disk drives can step up to 40 tracks), and on some PC-era drives like the Tandon TM-100 will format up to 42 tracks. Every extra track counts, and if you can make a minimal system disk, even removing the BASIC language, you can have about 50K+ free space, which will get you a few programs on disk, since most game programs range from 4-16K in size.

You need to consult the LDOS manual for which files are needed on the minimum system disk and which can be purged, then issue the command: PURGE :0 (S,I,Q=Y) and it will ask you each filename to delete; system, invisible or otherwise.

Hope this helps,

Ian.
 
I've managed to get two drives working with my trs-80.The cumana BBC drive and one of the PC floppy drives.I just happened to have a cable with the correct connectors so I just leave the system disk in drive :0 and any other disk I want to play with in drive :1 (when I go back to messing with dos I'm going to be putting the colons the wrong side of the drive letter now;-))
 
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