Re: Apple II-Or Come on people, It's a 20 year old computer

["Arkain" <rwking@no.usa.spam.net>]

Note: The medium was 80 track, not 35.

There were several problems with the original controllers though. Due to the
use of common grade components, the read-write head was too large to write
to individual consecutive tracks. So the (even?) tracks inbetween were
deemed "half-tracks". That brought the # down to 40. Some of the old A2+
hardware couldn't handle going the full 40 and would overwrite track #35
when trying to write to the last 5 tracks. So the original format was made
35 track.

Later versions of the disk controller didn't have the same track motion
limitations. That lead to a slew of formatting software to format disks at
40 tracks instead of the standard 35. I enjoyed using 160K floppies.

Arkain

Paul Schlyter <pausch@saafNOSPAM.se> wrote in message
news:8mmvs2$h32$1@merope.saaf.se...
> In article <398EC312.6A5F2124@blakespot.com>,
> Blake Patterson  <blake@blakespot.com> wrote:
>
> > Paul Schlyter wrote:
> >
> >> But I suppose the history matters too.  And at the time of the Apple
> >> II, it made great sense to use GCR, since it provided 100k instead of
> >> 60k or 80k of the MFM 5.25" disk formats of those days.
> >
> > Apple II 5.25" floppies were 143K actually.  Not too bad for the time.
>
> Later versions of Apple II 5.25" floppies were 140K = 143360 bytes
> (note that one KByte equals 1024 bytes, not 1000 bytes): 16
> sectors/track and 35 tracks, where each sector held 256 bytes of data.
>
> But the first version of Apple II floppies were 116480 bytes = 113.75
> bytes (13 sectors/track and 35 tracks, where each sector held 256
> bytes of data.), which admittedly is somewhat more than 100 Kbytes,
> but not that much more.
>
> The Apple Pascal system introduced the 16-sector 140K disk format
> in 1979/1980.  About a year later, DOS 3.3 arrived, which supported
> the 16-sector format too.  And in between, Softcard CP/M was released,
> with system diskettes in both 13-sector and 16-sector formats.
>
> --
> ----------------------------------------------------------------
> Paul Schlyter,  Swedish Amateur Astronomer's Society (SAAF)
> Grev Turegatan 40,  S-114 38 Stockholm,  SWEDEN
> e-mail:  pausch at saaf dot se   or    paul.schlyter at ausys dot se
> WWW:     http://hotel04.ausys.se/pausch    http://welcome.to/pausch