PIL-Box throughput

[Dave Frederickson]

(07-13-2015 11:01 PM)Christoph Giesselink Wrote:  

(07-13-2015 03:12 AM)Dave Frederickson Wrote:  Perhaps the Write also did a Verify.

Definitely not.

The reason is the LIF format itself. The LIF format does not have a File Allocation Table (FAT) like other disc formats, so the free sectors must be extracted from the directory structure by reading all directory entries. This is the additional time spend at writing.

You can make a try, just measure the time writing a file to a quite full LIF image with many directory entries and make another try writing the same file to a newly created empty LIF image. You will get a significant difference, especially on small files.

When optimizing the ILPilbox.exe bridge software JFG gave me the tip for the throughput write measurements to write the data from and to the HP71 itself. For the loop HP71-Pilbox-ILPer:

A=TIME @ COPY file TO :3 @ TIME-A

will do the job. Further, the performance of the ILPer host has also a big influence on the file throughput. I made tests with an old P4/3.2GHz and an 8 core Z600 workstation (2.66GHz nominal, 3.06GHz Turbo mode). The Z600 workstation was over 60% faster.

Hi Christoph,

I'm aware of the directory entries issue and that's why I INITIALIZED the image before executing ROMCOPY. Secondly, I COPYied a 13K file to ILPer and I got around 860 bytes/sec. Thirdly, if I omit the ;ROMSIZE=32768 then ROMCOPY fails after 34 seconds with "VERIFY FAILED". This seems to support my suspicion that ROMCOPY does a Verify after Writing. Did you notice that the Write time is exactly twice the Read time?

What rates do you measure?

Dave