Jeff Berryman

“ Sometimes even the warehouses get full. The Thing King then has to start piling things on the dump out back. This makes the game slower because it takes a long time to get things from the dump when they are needed in the workshop. The Thing King follows a rule that minimizes this delay: When the warehouse begins to get too full, the Thing King uses his spare time to move the grubbiest things in the warehouses out to the dump. This means that the most infrequently zarked things will end up in the dump so that the Thing King won't have to get things from the dump very often. ”

“ None Program B is better than Program A because it tends to require a smaller number of page-reads. This is true because Program B localizes its references; it does all its work on one page before moving on to the next, whereas Program A bounces its references back and forth from page to page. ”

“ Both of these programs do the same thing; Program B does it more efficiently. Why? Let's look at the array X in the context of paging. X is 2000 words long; each word takes 4 bytes, so X requires 8000 bytes of storage. Since each page is 4096 bytes of virtual memory, X takes a bit less than 2 pages. Since the elements of arrays like X are arranged in subscript order, X (1) and X (2) will fall in one page, while X (1999) and X (2000) will fall in another. ”

“ That is, the array elements for column 1 (for all rows) are stored at the beginning addresses of the array; next, in ascending addresses, are all of the elements of column 2, and so forth. The elements of column 250 occupy the highest addresses in the region of storage allocated to the array X. Note that the total size of this array is 1,000,000 bytes— four bytes for each of 250,000 array elements. This amounts to just about one-half of the total real memory if the entire array were paged-in. It is also worthwhile noting that each column requires 4000 bytes, or nearly a whole page. ”

“ Each player's stock of things is numbered in the same range, 1 to 8,000,000. The thing King always knows who owns what thing and whose turn it is, so you can't ever accidentally zark someone else's thing, even if one of your things has the same thing number. ”