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Model 4P and DD/HD drives / Software exchange

Stormtrooper of Death

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I posted this question also on facebook, but still didnt get lots of answers. So i post it in this group aswell:


Question 1: I have a TRS-80 model 4P with 2 Singlesided DD 5.25 drives. I am able to exchange software , using an old Pentium 2 that has a 3.5 inch drive and a 5.25 inch HD drive. Standard LDos and TRSDos floppies are copied oke, but I am not able to copy other floppies. I use "David Keil Model 3 en 4 emulator" on the MS-DOS Pentium 2. Tried CopyCat 4.1 several times. The progam writes to real 5.25 floppy, but when i insert the floppy in the model 4P, nothing works. Any hints / tips of what program to use for easy exchange of software/data between MS-DOS and TRS-80 ?


Question 2: About using newer DD/HD drives in my Model 4P. I have bought 2 old 5.25 inch 1.2MB HD floppy drives. One is a Mitsumi / Newtronics D509 , the other is a Ye Data YD-380C.


I read on the internet that the D509 has the jumpers to switch from DriveREady to DiskChange and jumpers to set the driveID (DS0, DS1, DS2, DS3). Can I use a plain cable with all 34 pins intact to connect one of these 2 HD drives (or can I use the standard drive cable that is already in the model 4P) ? The YD-380C also has 2 rows of jumpers that can be changed, but i dont have any info about the meaning of those.


Can I use a plain cable with all 34 pins intact to connect one of these 2 HD drives (or can I use the standard drive cable that is already in the model 4P) ?


My ideal setup in my 4P would be drive 1 to be the original TRS-80 drive (Single Sided/ Double Density) and drive 0 to become on of the above mentioned HD Double sided / Double Density drives.


Greetings from Richard Vermeulen (from the Netherlands)

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If the drive you are writing with is an 80-track drive (which an HD floppy always is), it will only write half of a 40-track track. If the disk was bulk-erased at the start, that might be enough, but without the bulk-erase, you get the data from two adjacent tracks interfering with each other. If you're just trying to get it going quick, try a big tape bulk-eraser on a disk before writing it, and make sure that you have a "double-step" option enabled when writing. Note that a "new" disk out of a box will likely already be formatted, unless it's really old. Also, do not use HD media to write in double-density, the magnetic properties of the disk are wrong for that.


You really need a 360K drive to write disks, unless you also have an 80-track drive on the TRS-80. The disk controller chip will also need to be able to write 256-byte sectors. I understand that many PC disk controllers can't do single-density, but you shouldn't need that on a Model 4P.


Floppy drives in a TRS-80 usually had a drive-select jumper in the drive, and a straight-through cable. On the Model I, I recall that the pin it used for DS3 was "officially" the Side Select pin, making it easy to add double-sided drives, as long as you only used three of them. As I recall, the most annoying thing about putting a "modern" drive in is that the screw hole locations were different from PC-era drives, making it a pain to fit two drives into a Model III/IV full-height hole.


But I really wouldn't recommend an HD drive on a TRS-80, since the drive controller doesn't know about the HD signals, particularly the density select. If you do use one, you will probably need a jumper to force it to double density.

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I bought 2 Panasonic JU-455-5 5.25 floppy drives last week for my 4P. These JU-455 are 360K double sided drives. I had some problems trying to connect them, but now all is working nice.


I am now using the original single sided floppy drive as :0 and the new 360K drive as :1


lots of fun using the old model 4P. Since i had it repaired, i use it almost every day.

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