[TUHS] Mach for i386 / Mt Xinu or other

Diomidis Spinellis dds at aueb.gr
Wed Feb 22 01:54:13 AEST 2017


On 21/02/2017 17:18, Joerg Schilling wrote:
>> Requiring "pass through SCSI" for a CD burner violates the UNIX
>> philosophy that everything is a file (which implies that reading and
>> writing data be implemented, where possible, through the read and write
>> system calls rather than through special interfaces specific to a device
>> type).
>
> You are incorrectly informed:
>
> Writing CDs is a highly complex task. No known kernel is able to do that
> internally.
>
> So the only useful method is to use SCSI pass through.

This is an interesting point.  However, controlling the C/A/T 
phototypesetter 20 years before writable CD-ROM appeared, was also a 
very complex task, yet it was accomplished through a simple device file. 
  Controlling a voice modem is also complex, time-critical, and requires 
bidirectional communication. Again, voice modems were controlled through 
a character device file.

One can envisage a CD-ROM device driver abstracting the commands 
required for writing CD-ROMs into a text-based interface made available 
though a character device.  These precedents demonstrate that the SCSI 
pass through was an unneeded architecture-violating shortcut.

Arguably, the same can also be claimed for the networking system calls.

Diomidis



More information about the TUHS mailing list