Is automatic “folding” of programs efficient enough to displace manual?

ABSTRACT

The operation of “folding” a program into the available memory is discussed. Measurements by Brawn 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'Neill, 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.

REFERENCES

• 1: BRAWN, B. S., AND GUSTAVSON, F. G. An evaluation of program performance on the M44/44X system, Pt. I. IBM Res. Rep. RC-2083, May 8, 1968. Pts. II and III (RC-2275; Nov. 7, 1968 and RC-2276, Jan. 6, 1969) also available. The report is summarized in B. S. Brawn and F. G. Gnstavson, Program behavior in a paging environment. Proc. AFIPS 1968 Fall Joint Comput. Conf., Vol. 33, Thompson Book Co., Washington, D. C., pp. 1019-1032.
• 2: NELSON, R. A. A queueing approach to the replacement problem in paging machines. IBM Res. Rep. RC-2262, Oct. 23, 1968.
• 3: O'NEILL, R. W. Experience using a time-shared multi-programming system with dynamic address relocation hardware. Proc. AFIPS 1967 Spring Joint Comput. Conf., Vol. 30, Thompson Book Co., Washington, D. C., pp. 611-621.
• 4: LINDQUIST, A. B., SEEBER, R. R., AND COMEAU, L. W. A timesharing system using an associative memory. Proc. IEEE 54, (Dec. 1966), 1633.
• 5: McKELLAR, A. C., AND COFFMAN, E. G. The organization of matrices and matrix operations in a paged multi-programming environment. Tech. Rep. 59, Princeton U. Dept. of Electrical Engineering, Comput. Sci. Lab., Feb. 1968.
• 6: O'NEILL R. W., AND SHILS, A. J. Unpublished work.

INDEX TERMS

Primary Classification:
  D. Software

General Terms:
Algorithms

Keywords:
automatic folding, automatic paging, demand paging, folding, measurement, memory hierarchies, paging, performance, replacement algorithms, storage hierarchies