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Today I learned: Cassette timings

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  Today I learned: Cassette timings John Elliott <jce@seasip.demon.co.uk> - 2014-08-16 00:34 +0100
    Re: Today I learned: Cassette timings "Brian Gaff" <brian1gaff@gmail.com> - 2014-08-16 11:12 +0100
      Re: Today I learned: Cassette timings John Elliott <jce@seasip.demon.co.uk> - 2014-08-16 19:56 +0100
        Re: Today I learned: Cassette timings John Elliott <jce@seasip.demon.co.uk> - 2014-08-23 23:38 +0100
        Re: Today I learned: Cassette timings greenaum@gmail.com (greenaum) - 2014-09-03 01:46 +0000
          Re: Today I learned: Cassette timings John Elliott <jce@seasip.demon.co.uk> - 2014-09-03 21:59 +0100
    Re: Today I learned: Cassette timings leespoons <10000spoons@gmail.com> - 2014-08-19 14:59 +0000
      Re: Today I learned: Cassette timings greenaum@gmail.com (greenaum) - 2014-09-03 01:44 +0000

#3146 — Today I learned: Cassette timings

  The cassette timings for the IBM PC 5150 are close enough to the
Spectrum ones that it will load 'normal speed' blocks from a TZX played back
by PlayTZX.

  To get technical:

                Spectrum         5150
   Pilot tone   2168T / 2168T    1750T / 1750T    
   Sync pulse    667T /  735T     875T /  875T
   Zero bit      855T /  855T     875T /  875T
   One bit      1710T / 1710T    1750T / 1750T

  There's an example TZX of a 5150 BASIC program at 
<http://www.seasip.demon.co.uk/ZX/Haunted/hauntx.tzx>. It contains four
blocks:

'Turbo' block giving a leadin tone.
'Normal' block containing the BASIC header:   263 bytes 
'Normal' block containing the BASIC program: 8519 bytes
'Turbo' block giving the leadin tone again.

The first three blocks were generated by VOC2TZX. I found I had to add the 
last block manually (it's a duplicate of the first) or the load would fail.

-- 
John Elliott

Thinks: This is what a nice clean life leads to. Hmm, why did I ever lead one?
		-- Bluebottle, in the Goon Show

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#3148

And what would be the ultimate goal of this?
 We used to load tapes in vie the parallel port in the good ol days.
 Brian

-- 
From the Sofa of Brian Gaff Reply address is  active
"John Elliott" <jce@seasip.demon.co.uk> wrote in message 
news:e0i2cb-hgu.ln1@seasip.demon.co.uk...
>  The cassette timings for the IBM PC 5150 are close enough to the
> Spectrum ones that it will load 'normal speed' blocks from a TZX played 
> back
> by PlayTZX.
>
>  To get technical:
>
>                Spectrum         5150
>   Pilot tone   2168T / 2168T    1750T / 1750T
>   Sync pulse    667T /  735T     875T /  875T
>   Zero bit      855T /  855T     875T /  875T
>   One bit      1710T / 1710T    1750T / 1750T
>
>  There's an example TZX of a 5150 BASIC program at
> <http://www.seasip.demon.co.uk/ZX/Haunted/hauntx.tzx>. It contains four
> blocks:
>
> 'Turbo' block giving a leadin tone.
> 'Normal' block containing the BASIC header:   263 bytes
> 'Normal' block containing the BASIC program: 8519 bytes
> 'Turbo' block giving the leadin tone again.
>
> The first three blocks were generated by VOC2TZX. I found I had to add the
> last block manually (it's a duplicate of the first) or the load would 
> fail.
>
> -- 
> John Elliott
>
> Thinks: This is what a nice clean life leads to. Hmm, why did I ever lead 
> one?
> -- Bluebottle, in the Goon Show 

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#3150

Brian Gaff <brian1gaff@gmail.com> wrote:
> And what would be the ultimate goal of this?

  A more convenient way of distributing or archiving such cassette software 
for the PC as exists.

-- 
John Elliott

Thinks: This is what a nice clean life leads to. Hmm, why did I ever lead one?
		-- Bluebottle, in the Goon Show

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#3168

John Elliott <jce@seasip.demon.co.uk> wrote:
> Brian Gaff <brian1gaff@gmail.com> wrote:
>> And what would be the ultimate goal of this?
> 
>  A more convenient way of distributing or archiving such cassette software 
> for the PC as exists.

  I've now updated the taptools at <http://www.seasip.info/ZX/unix.html> so
that they can generate and manipulate files with IBM PC headers rather than 
Spectrum ones. This means it's possible to get an ASCII listing into a
cassette-only 5150 by doing this:

mkibmtap -n orient.tzx -a orient.bas
playtzx orient.tzx

-- 
John Elliott

Thinks: This is what a nice clean life leads to. Hmm, why did I ever lead one?
		-- Bluebottle, in the Goon Show

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#3196

I can't think of much less convenient than finding an IBM 5150 with a
tape interface! Did they sell many? Even in the early days, if you
were gonna waste money on an IBM, you'd have enough to burn buying a
5.25" floppy drive or two. Even if those drives were 400 quid!

---------------------------------------------------------------------

"hey let's educate the brutes, we know we are superior to them anyway,
just through genetics, we are gentically superior to the working
class. They are a shaved monkey. If we educate them, they will be able
to read instructions, turn up on time and man the conveyor belts,
sorted."     #     

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#3198

greenaum <greenaum@gmail.com> wrote:
> I can't think of much less convenient than finding an IBM 5150 with a
> tape interface! Did they sell many? Even in the early days, if you
> were gonna waste money on an IBM, you'd have enough to burn buying a
> 5.25" floppy drive or two. Even if those drives were 400 quid!

  All 5150s have the cassette interface, whether or not they also have 
floppy drives.

-- 
John Elliott

Thinks: This is what a nice clean life leads to. Hmm, why did I ever lead one?
		-- Bluebottle, in the Goon Show

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#3163

John Elliott <jce@seasip.demon.co.uk> wrote in
news:e0i2cb-hgu.ln1@seasip.demon.co.uk: 

>   The cassette timings for the IBM PC 5150 are close enough to the
> Spectrum ones that it will load 'normal speed' blocks from a TZX
> played back by PlayTZX.
> 
>   To get technical:
> 
>                 Spectrum         5150
>    Pilot tone   2168T / 2168T    1750T / 1750T    
>    Sync pulse    667T /  735T     875T /  875T
>    Zero bit      855T /  855T     875T /  875T
>    One bit      1710T / 1710T    1750T / 1750T
> 
>   There's an example TZX of a 5150 BASIC program at 
> <http://www.seasip.demon.co.uk/ZX/Haunted/hauntx.tzx>. It contains
> four blocks:
> 
> 'Turbo' block giving a leadin tone.
> 'Normal' block containing the BASIC header:   263 bytes 
> 'Normal' block containing the BASIC program: 8519 bytes
> 'Turbo' block giving the leadin tone again.
> 
> The first three blocks were generated by VOC2TZX. I found I had to add
> the last block manually (it's a duplicate of the first) or the load
> would fail. 
> 

Interesting. I found out recently that the Apple-II uses very similar 
timings to the Spectrum, including the leader:

http://www.brutaldeluxe.fr/projects/cassettes/

Not sure if there's a way of loading this into a real Speccy, but it 
certainly sounds like one! (10-second leader instead of 5 for the 
Speccy)

AFAIK this was 4 years before the IBM PC (and 5 before the Speccy) - 
makes me wonder why it wasn't more widely used given the slow baud rates 
of (say) the ZX81 or C64...

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#3195

I'll just add "Kansas City Standard" here. Dunno if it applies, but
the easiest way to explain would be for anyone interested to look it
up. It's a standard for cassette tape data storage.

---------------------------------------------------------------------

"hey let's educate the brutes, we know we are superior to them anyway,
just through genetics, we are gentically superior to the working
class. They are a shaved monkey. If we educate them, they will be able
to read instructions, turn up on time and man the conveyor belts,
sorted."     #     

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