On Thu, 25 Oct 2007 10:48:22 -0500, Eric Bielefeld <eric- [EMAIL PROTECTED]> wrote:
>What do you mean by radix sort? Did anybody anwer that question yet? I didn't see one. A radix sort is one that processes each possition of the key at a time. For a decimal key it simply separates the input into 10 strings. You then take outputs in in ascending sequence (at least for a least-significant-digit-first radix sort), feed that combined batch back into the hopper, selected the next key possition and repeat. For non-numeric keys you have to make multiple passes on the same column, picking up the zone punches as if they were between the columns. >... Also, all the sorters I've ever seen had 12 pockets, not 10. ... I suspect you are right, but for a radix sort the extra two wouldn't be needed. For a standard encoding like EBCDIC alphanumeric you need only 0-9 for numerical or 0-7 (for zone) plus 1-9 (for digit for alphabetical. (I have no idea how you handle all 256 punch combinations, but I know it was done, and I suspect it needed 10 or fewer stackers ... but many passes.) The person Howard quoted said "the machine was the size of >a wall. I've never seen a sorter I'd call that big, ... I guess it depends on the size of your walls. :-) >... >360 Mod 20 to sort small decks of cards. It was faster on small >decks with over 10 columns to sort on. I don't remember sorting >much alphabetically, but I'm sure I did it. I don't remember what sorting technique the mod 20 Sort/Merge used, but it was definitely not a radix sort. For one thing, it compared the whole key, not individual single positions. It also had the wonderful characteristic of telling you how many more passes were needed. And if you happened to transfer the cards from stacker to hopper in the wrong order you simply increased the number of passes a little bit. If you did that on the card sort machine you'd better remember which column you screwed up on because you had to redo the sort from that column on. And if you happened to get a card jam on one of the big sorters you were in big trouble. They fed cards so fast that many were mangled before it could shut down. The mod 20's MFCM was slow enough to damage very few cards. (Of course, with the MFCM, a card jam was almost guaranteed.) Pat O'Keefe ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
