Re: Card Edge connector for TRS-80

"Larry" <larry_fos***@xxxxxxxxxxx> writes:


"sylvan butler" <ZsdbUse1+noZs_0607@xxxxxxxxxxxxxxxxxxxxx> wrote in message
news:slrneal5j6.mr0.ZsdbUse1+noZs_0607@xxxxxxxxxxxxxxxxxx
On Fri, 30 Jun 2006 02:14:52 GMT, Larry <larry_fos***@xxxxxxxxxxx> wrote:
The connectors are called "IDE card edge connectors".

Funny, that must be new. What does IDE stand for? But notice the JDR
page has other errors... Since when does a 40-pin connector have its
connectors arranged 2x10? I think them calling it "IDE" is a simple
shortcut by people who don't know/care the difference.

I don't know when/where it started. Maybe E = edge?

IDE as it applies to the 40-pin disk drive interface stands for
"Integrated Drive Electronics".

Back in the TRS-80 days, hard drives didn't contain their own controllers;
the controller card was part of the computer and the raw data signal from
the read heads was passed along the data cable from the disk drive. So the
controller was part of the computer. The IDE design moved the controller
into the device, which was a big improvement in several areas :-

- raw data from the read heads travelled only a short distance to the
inbuilt controller, improving reliability as the signal did not have
to travel down a long cable. This meant data rates could increase.

- the inbuilt controller standardised and simplified the interfacing of
the device to a computer. We soon saw innovation in that interface,
as the ATA-1 standard was enhanced with things like Ultra-DMA.

- the inbuilt controller permitted innovations in physical storage
techniques. The host computer became ignorant of the exact data
recording method; it became something private to the device. MFM
encoding gave way to RLL, and later PRML and EPRML. Also drives
became free to implement bad sector remapping, read and write
caching, different sector layouts and more.

Floppy drives on the other hand, appear to have not evolved much
since the 1980s. The 34-pin interface to a 3.5" floppy drive is
signal-compatible to the 34-pin interface used by the TRS-80s,
and so the FDC controller chip on the motherboard is responsible
for decoding the raw data from the read/write heads.

Nick.
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