Re: [M100] Clock Doubler Video

[birt_j]

Even at the normal clock rates the TS-DOS timing issues can cause lock ups. In 
normal use one might only stumble on this occasionally. I noticed this testing 
Backpack drives when I’m doing a lot of the same operations over and over again.

It seems to stem around pressing the next button you want before it is down 
drawing the screen. If I don’t get in a hurry and wait for a second after each 
screen is drawn it never locks up. I suspect that the faster clock exacerbates 
this latent bug. 

 

Jeff Birt

 

From: M100  On Behalf Of Stephen Adolph
Sent: Friday, February 16, 2024 2:16 PM
To: m...@bitchin100.com
Subject: Re: [M100] Clock Doubler Video

 

Ken ,

What a great job you've done!  Thank you sir.

You really did a nice job with the assembly and commentary on how to install it.

At some point I have to find out why Starblaze video is broken

I'm adding the upgrade to all my machines to try and get as much experience 
with it as possible.

 

I have noticed that TSDOS sometimes does not work in 5MHz mode, whereas Teeny 
does.  So that has to be a software and timing issue to sort out.

 

Thanks again Ken!  Cheers Steve

Re: [M100] Clock Doubler Video

[Stephen Adolph]

Ken ,
What a great job you've done!  Thank you sir.
You really did a nice job with the assembly and commentary on how to
install it.
At some point I have to find out why Starblaze video is broken
I'm adding the upgrade to all my machines to try and get as much experience
with it as possible.

I have noticed that TSDOS sometimes does not work in 5MHz mode, whereas
Teeny does.  So that has to be a software and timing issue to sort out.

Thanks again Ken!  Cheers Steve

On Friday, February 16, 2024, Ken St. Cyr  wrote:

> Hi folks -
>
> Just wanted to share that I released a video today detailing my journey in
> building and installing Steve Adolph's clock doubler mod:
>
> Adding TURBO MODE to the Tandy Model 100 (youtube.com)
> 
>
> I really enjoyed this one, and am super appreciative of Steve for
> patiently answering all of my questions and helping me understand how it
> all worked so I could explain it (hopefully) semi-adequately in the video.
> I've been using the mod daily for the past couple of weeks now, and while
> there are some quirks, once you have that speed boost, it's hard to live
> without it!
>
> I know Steve's not planning on selling any kits, but I do have a couple of
> boards and parts left over. If you're interested in one, please feel free
> to reach out to me directly and we can arrange something -
>
> Thanks -
> //Ken S.
>

[M100] Clock Doubler Video

[Ken St. Cyr]

Hi folks -

Just wanted to share that I released a video today detailing my journey in 
building and installing Steve Adolph's clock doubler mod:

Adding TURBO MODE to the Tandy Model 100 
(youtube.com)

I really enjoyed this one, and am super appreciative of Steve for patiently 
answering all of my questions and helping me understand how it all worked so I 
could explain it (hopefully) semi-adequately in the video. I've been using the 
mod daily for the past couple of weeks now, and while there are some quirks, 
once you have that speed boost, it's hard to live without it!

I know Steve's not planning on selling any kits, but I do have a couple of 
boards and parts left over. If you're interested in one, please feel free to 
reach out to me directly and we can arrange something -

Thanks -
//Ken S.

Re: [M100] dice

[B 9]

On Wed, Feb 14, 2024 at 7:44 AM John R. Hogerhuis  wrote:

That's pretty cool. How many bits does the QR convey?
>
That’s a surprisingly complex question. The short answer is that this 21 x
21 pixel QR code could hold up to seventeen 8-bit binary characters.
(Phones seem to recognize the characters as standard Unix UTF-8 Unicode
encoding, which is a superset of ASCII where characters beyond ASCII use
two or more bytes.)

Longer answer: Besides having different sizes — from Version 1 at 21x21 to
Version 40 at 177 x 177  —
even at the same dimensions QR codes have various compression and error
correction modes which means the size of the payload varies. For example,
if the data was in all caps (plus some punctuation), a 21 x 21 QR can fit
25 characters, instead of just 17. If it was purely numeric, you could fit
41.

Longest answer: But, you asked for a measurement in bits, not characters,
which gets a bit hairier. Of the 441 bits (21×21) the Model T is showing,
here are the ingredients:
Usage Bits
Three 8x8 alignment patterns 192
…plus two 5 pixel dotted lines connecting them 10
…plus one black pixel at top right of lower left square 1
Format info (ECC level and mask pattern) 15
Format (Duplicate) 15
Error Correcting Code data 56
Length 8
Encoding 4
End 4
Seventeen 8-bit characters 136

So, how many bits are conveyed? It depends upon what you count, but I’ll
stick with 136.

You can play around with different setting at this nifty QR encoder:
http://www.ee.unb.ca/cgi-bin/tervo/qrcode.pl

Another question you might ask: How large of a QR code could a Model T
show, theoretically? IIRC, the Model 100 screen was 64 pixels high. QR code
sizes are called “versions” and Version 11 would fit at 61x61 pixels. Using
the lowest ECC level, Version 11 conveys 321 bytes.

On my Tandy 200, the screen is 128 pixels high, so theoretically one could
show a Version 27 (125x125) QR code which could contain 1465 bytes. At that
point, you'd want to calculate the QR code on the Model T as the bitmap
would take 1954 bytes of storage, at a minimum.

—b9

P.S. I notice that the ASCII Pixels pbm2ap.c

program will happily generate images which are too long to store in a BASIC
string (255 characters). I do not know if that means there is some way to
actually display such images. I suspect not since the first byte of the
string is the length.

$ convert granite: -geometry 41x41 foo.pbm
$ ./pbm2ap foo.pbm foo.ap
PBM to AsciiPixels Converter
Version 1.0
Copyright 2017, Ken Pettit
BSD 3-clause license
Image size: X=41, Y=41
$ wc -c foo.ap268 foo.ap
$ cat foo.ap