Re: cdrtools cdrecord/cdrecord.c

[Gene Heskett <gene.heskett@verizon.net>]

On Saturday 21 January 2006 19:06, Steve McIntyre wrote:
[...]
>--
>Steve McIntyre, Cambridge, UK.                               
> steve@einval.com Getting a SCSI chain working is perfectly simple if
> you remember that there must be exactly three terminations: one on
> one end of the cable, one on the far end, and the goat, terminated
> over the SCSI chain with a silver-handled knife whilst burning
> *black* candles. --- Anthony DeBoer

Are virgins that hard to find these days?  There have been times when I 
considered it, but couldn't find one.

OTOH, if the scsi bus is treated as a transmission line that must be 
PROPERLY terminated, then it generally works as expected.  But you 
would not believe the sloppily done terms I've fixed over the years.  
Termpaks soldered in bas ackwards are the first thing to check, its not 
a zero percentage occurance by any means.  Low 5 volt supply combined 
with a junkbox si diode for host isolation is another killer, the ttl 
level specs cannot be achieved for level 1 signals with only 4.1 volts 
after the host isolation diode.  Go ahead, calculate the resting 
voltage and be amazed that it works as well as it does 99% of the time.

Or, better yet, get out a dvm and measure the resting voltages on the 
signal lines of the bus.  Anything under 2.75 volts is a data error at 
some point in time, with 2.9 to 3.0 being considered the holy grail.

Thats also why its not recommended to mix active and passive terms, the 
passive terms are so far off that they can draw enough power to 
overheat the active terms internal regulators, possibly even letting 
out the smoke.

OTOH, thats yet another chapter in comp sci.  One the bean counters in 
management skipped.

-- 
Cheers, Gene
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