Here, dspGuru explains how to search postings to comp.dsp (or other Usenet newsgroups).
Several comp.dsp archives used to be available on the net, but Google now seems to be the only one left. (Evidently it's hard to make a buck selling Usenet blather. ;-)
DejaNews started archiving all of Usenet in 1995. DejaNews was a beautiful thing in its time, offering a free, fast, and powerful search capability into a vast, sticky mess. However, at some point DejaNews changed their name "Deja"; then their corporate pinheads forgot that their service was supposed to be about newsgroups. (Or maybe their IPO money just ran out. ;-)
The older posts were unavailable for a long time, starting about the same time that the other archives folded up, so they were unavailable, period. Loyal users of Usenet said:
Fortunately, Google acquired Deja's archive, and then put it back on the air. Google still doesn't present posts as nicely as DejaNews did in its prime, but the posts are available again, and the search works well. (And that's what really counts!)
Google provides two search interfaces, a basic search and an advanced search.
Search Tips: