Bit of DEC Trivia

I have gone through 2 boxes of TU-58 tapes with about 200 tapes in each box plus other odd assorted tapes for a total of about 500 tapes in all. I know of a number of other sites which have used several thousand tapes. At one time, the PDP-11/44 and the VAX 780 used the TU58 media as distribution tapes. How many installations existed? If you are referring, in particular, to the TU-58 tape media, then it seems a bit unlikely that if I can personally be aware of between 3000 and 5000 TU-58 tape media, that my experience will not have been duplicated a few hundred times for a total of over a million TU-58 tapes. If you have exact shipping information on how many TU-58 tapes DEC ever sold and shipped, then I will agree to that limited number. Otherwise, for a quick estimate, I can probably stack 30 to 50 TU-58 tapes (in their plastic containers for better stability) on a 1 TB HDD. With a capacity of 512 blocks (of 512 bytes per block - or a normal HDD block size) for each TU-58 tape and approximately 1,000,000,000,000 divided by 512 bytes (or about 1,953,125,000 blocks) on a 1 TB HDD, my estimate would be close to 3,814,697 TU-58 tape images could fit on a raw 1 TB HDD when no additional information such as a file structure is used. RT-11 would be ideal in that case if used to access the information. If 465 files, each with exactly 2,147,483,648 bytes each holding 8192 TU-58 tape images each were allocated on a 1 TB HDD with additional room for a FAT32 file structure, that would hold 3,809,280 TU-58 tape images. RT-11 under Ersatz-11 could easily access each of the TU-58 tape images in that case without a separate file structure being required for each of the 2 GB files. This would be an actual solution that will work, aside from the practical problem if some sort of index system to keep track of the contents of the 3,809,280 TU-58 images. But then you did not say that it was necessary to keep the index system for the TU-58 tape images on the same 1 TB HDD. I believe that is a bit more than the 3,086,419 TU-58 tape images previously estimated. Jerome Fine