The following are frequently asked questions concerning USP.
If you have a question that is not covered by the following
call us (Paul Garossino, Joe Wade, Paul Gutowski, Bryan Helvey)
and we will not only answer your question [hopefully]
but also add it to the list. If you find the following wording
inadequate feel free to write a better description and mail it
to us. We will replace the current verbiage with your offering.
Hopefully this FAQ will help users up the USP learning curve.
Questions
1.0 What is the easiest way to reciprocate a dataset?
2.0 I ran [davc -N data1 -Odata1 -w 1000 -amp22.0], the job bombed
and my data was erased. What gives??? ;-<
3.0 Where can I find a reference for all the line and trace header mnemonics in USP?
4.0 Why does ufh tend to run very slow on very large datasets?
5.0 I created a USP dataset on 8mm tape using dd bs=32768 on a Solaris system. I tried to read it on a Linux system and got an I/O error, what gives?
Answers
1.0 What is the easiest way to reciprocate a dataset?
Use program scale with an exponent of -1
[scale -exp -1 ]
2.0 I ran [davc -N data1 -O data1 -w 1000 -amp22.0], the job bombed
and my data was erased. What gives??? ;-<
In USP datasets attached at -N are opened for read access
while datasets attached at -O are opened for write access.
In UNIX you can do both simultaneous. Unfortunately the open
for write access put the file pointer at the start of the file
which is equivalent to erasing your file. This is a pitfall
in USP which most users hit ONCE. Sorry.
3.0 Where can I find a reference for all the line and trace header mnemonics in USP?
You can view this information in the man page for program scan or for dds_usp. You can also see the control file used by our code during compilation at: /home/usp/include/save.h.
4.0 Why does ufh tend to run very slow on very large datasets?
If your dataset is over say....10GBytes you will find that writing a full blown program will far outperform ufh in throughput. When ufh was invented a 2Gbyte dataset was all that could be handled. The author was driven out of the company prior to filesystems that could handle >2Gbyte files. It it probably time to revisit the code specifically for large file performance. Of course now we are merged and have no one with the time to do such a thing................unless you want to give it a try. Martin Smith [the author] has kept the product development over the years and has a version that I am sure he would sell us that is probably a better performer.
5.0 I created a USP dataset on 8mm tape using dd bs=32768 on a Solaris system. I tried to read it on a Linux system and got an I/O error, what gives?