Gary, so did I ! Could it be that a TPDD just formats 40 tracks and a TPDD2 80 ?
Assuming single-density recording, that would come out right, I think. I remember that a TRS-80 standard SD disk recorded about 85 KB on 35 tracks. That would be on 40 tracks: 85 KB * 40 / 35 = 97 KB. That fits. By the same calculation, a TPDD2 would write 200 K over 80 tracks Testing this hypothesis would be easy. Since a TPDD2 can read TPDD disks, A TPDD should be able to read TPDD2 disks, but only the first bank! Does anybody have the hardware to test this ? (ie., a Model T and both a TPDD and a TPDD2) Or, observe a TPDD2 in action and see where it writes data in Bank 1, and where in Bank 2. After all these years ... Greetings from the TyRannoSaurus / Jan-80@work > After rereading this I wanted to make one critical point. Remember, if > yours is truly the TPDD2, it already is double sided. It formats the drive > as 100K per side (200K total). You use the "Bank" feature in TS-DOS to > switch between which side you're accessing. So, no need to be fantasizing > about flippy-floppies. ;-) But wait! This is the story that I believed for years, as it was told to me by *someone* out there. And having not ever closely examined the drive to see if there's *actually* two read/write heads, I believed it. Until tonight. The "Bank" feature definitely accesses the second 100k, but smack me upside the head please: There's only one drive head! So please disregard everything I said before; apparently the 200k format is just higher density (closer track spacing??). All these years, believing something incorrect... Feel free to commence fantasizing about 3.5" flippy-floppies once again. ;-) On Mon, Aug 7, 2017 at 9:39 PM, Gary Weber <m100l...@gweber.org> wrote: >> Double-sided doesn't hurt anything of course, although it's too bad you >> can't make 3.5" flippy disks as easily as you could 5.25"! > > After rereading this I wanted to make one critical point. Remember, if > yours is truly the TPDD2, it already is double sided. It formats the drive > as 100K per side (200K total). You use the "Bank" feature in TS-DOS to > switch between which side you're accessing. So, no need to be fantasizing > about flippy-floppies. ;-) > > It was the original TPDD that is only 100K single sided. > > Gary > > > On Mon, Aug 7, 2017 at 8:04 PM, Kurt McCullum <kurt.mccul...@att.net> wrote: >> >> Thanks Brian & Garry, >> >> >> >> I suspected that to be the case but when my HD disk appeared to work I >> thought I would ask. >> >> >> >> Kurt >> >> >> >> From: M100 [mailto:m100-boun...@lists.bitchin100.com] On Behalf Of Brian >> White >> Sent: Monday, August 07, 2017 4:41 PM >> To: m...@bitchin100.com >> Subject: Re: [M100] 3.5" Media >> >> >> >> I wasn't using these when they were current, but... No question double >> density. Aside from the dates when these things were sold, or the fact that >> the actual formatting is far less than double density, or the fact that the >> original utility disk that came with it is double density, which are each >> solid points on their own... >> >> >> >> The manual for PDD-2 says to use cat 26-415 or 26-416, >> >> and those catalog numbers are not only double density but actually single >> sided. >> >> >> >> Double-sided doesn't hurt anything of course, although it's too bad you >> can't make 3.5" flippy disks as easily as you could 5.25"! >> >> >> >> But trying to use SD/DD read/write head signal strength on HD media is >> going to either not work at all, or work very poorly/unreliably, or worse, >> *appear to work but be corrupt*. Because the HD media is more sensitive than >> the older media, and operates at lower signal strengths than the older >> media. An SD or DD drive write signal is stronger to match the weaker media >> it was meant for. So in effect you are over-driving the newer media. In >> plain audio you can tell when that's happening because you actually hear the >> distortion like a ripped speaker. As data, you can't hear it directly or >> tell it's happening, which makes it more dangerous. They should have made HD >> disks so they don't even fit in older drives. Make them slightly longer >> maybe, so that old disks could still fit in new drive, but new disks >> couldn't fit in old drives. The guy who sent me my copy of the utility disk >> sent one of each type, and the HD copy actually works, which is what I mean >> by "dangerous", because, going by that, you would conclude "It works, so, it >> works." >> >> Jump to page 6 >> >> http://www.classiccmp.org/cini/pdf/Tandy/Portable%20Disk%20Drive%202%20Operation%20Manual.pdf >> >> Jump to page 41 >> >> http://www.colorcomputerarchive.com/coco/Documents/Radio%20Shack%20Catalogs/Tandy%20Computer%20Catalog%20and%20Software%20Reference%20Guide%20(1988)(Tandy).pdf >> >> That catalog doesn't say DD explicitly, but it does say others are HD and >> 1.44M explicitly, which makes everything else not-HD by omission. >> >> I assume that somewhere a more authoritative reference on the catalog >> numbers would show that more explicitly. >> >> -- >> >> bkw >> >> >> >> On Mon, Aug 7, 2017 at 6:41 PM, Gary Weber <g...@web8201.com> wrote: >> >> Double Density for sure. A long time ago, I had attempted to format a >> high density disk on a TPDD2 but it gave an error. I've always had >> to use double density disks. >> >> >> On Mon, Aug 7, 2017 at 2:33 PM, Kurt McCullum <kurt.mccul...@att.net> >> wrote: >> > For those who have used a TPDD2 in the past, I have a question about >> > media >> > type. Do these drives prefer double density (720k) or high density >> > (1.44mb) >> > media? I've tested with both from by using recycled media from years >> > gone by >> > and both seem to work. My primary interest in the drive is to see if I >> > can >> > improve mComm but as I'm testing, I'd like to actually use the proper >> > media. >> > >> > Kurt >> > >> >> >> -- >> Gary Weber >> g...@web8201.com >> >> > > -- Gary Weber g...@web8201.com [http://www.vivaqua.be/facebook.png] Rejoignez-nous sur Facebook - Volg ons op Facebook DISCLAIMER Pensez à l'environnement, n'imprimez cette page et ses annexes que si c'est nécessaire. 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