An alternative

This alternative I am about to describe was considered at the start of our project, but rejected as not general enough. It acknowledges the one successful use of maps, the use of shared, read only programs. All other uses are discarded. There will be two forms of data storage:

i)

ECS files

ii)

disk files

An ECS file will be a simple sequence of words, there will be no division into data blocks. A disk file will be a simple sequence of equal sized records, each of which is a sequence of words. (This directly reflects the physical structure of the disk.) Actions will be available to read the contents of one or more consecutive, complete, disk file records into continguous words of an ECS file. There will be a similar action to write consecutive disk file records from an ECS file. There will be separate actions to transfer consecutive words between an ECS file and the local memory of a subprocess. A subprocess local memory will be specified in two parts. (The vestiges of a map.) Each part will be an entire ECS file. When a subprocess is swapped into CM, the two ECS files will be copied into CM; and when swapped out, one of the files will be copied back to ECS. Thus one of the files contains read only code, while the other contains data local to this version of the subprocess.