Is Automatic "Folding" of Programs Efficient Enough To Displace Manual? The operation of "folding" a program into the available memory is discussed. Measurements by Brown et al. and by Nelson on an automatic folding mechanism of simple design, a demand paging unit built at the IBM Research Center by Belady, Nelson, O'Neil, and others, permitting its quality to be compared with that of manual folding, are discussed, and it is shown that given some care in use the unit performs satisfactorily under the conditions tested, even though it is operating across a memory-to-storage interface with a very large speed difference. The disadvantages of prefolding, which is required when the folding is manual, are examined, and a number of the important troubles which beset computing today are shown to arise from, or be aggravated by, this source. It is concluded that a folding mechanism will probably become a normal part of most computing systems. CACM December, 1969 Sayre, D. paging, automatic paging, demand paging, folding, automatic folding, storage hierarchies, memory hierarchies, replacement algorithms, performance, measurement 4.0 4.19 4.39 6.20 6.34 CA691202 JB February 15, 1978 4:33 PM 1810 5 1810 1810 5 1810 1810 5 1810 2218 5 1810 2373 5 1810 1380 6 1810 1410 6 1810 1572 6 1810 1728 6 1810 1751 6 1810 1751 6 1810 1752 6 1810 1810 6 1810 1810 6 1810 1879 6 1810 1951 6 1810 2095 6 1810 2374 6 1810