Interesting. The bank feature is one of the areas I am looking into right now. 
Somehow, TS-DOS is able to determine if the drive is a TPPD2 and then the Bank 
feature is turned on. According to the manual, 200k is always available 
regardless of what bank you are in. It's not split 100k/100k. Each bank appears 
to have its own file allocation table with a maximum of 40 filenames.

I have not had much time with the drive yet but I'm curious if I can emulate 
the bank feature in mComm to have two directories supported at the same time. 
So in TEXT or BASIC a file save such as "0:XXXXXX.DO" would go to the active 
directory and "1:XXXXXX.DO" would point to an alternate location.

I don't know if it's possible but I plan to look into it.

Kurt
-----Original Message-----
From: M100 [mailto:m100-boun...@lists.bitchin100.com] On Behalf Of Gary Weber
Sent: Tuesday, August 08, 2017 12:33 AM
To: m...@bitchin100.com
Subject: Re: [M100] 3.5" Media

> 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%20Ca
>> talogs/Tandy%20Computer%20Catalog%20and%20Software%20Reference%20Guid
>> e%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

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