{nonref}Philosophy

In the progress of a computation the requirements for storage come and go. Some program manages the address segment and that program must be able to acquire fresh pages and nodes. There is not a single source of such things, but there is a standard way of calling for them. A start key whose program obeys these standards is called a (_“space bank”.)

Many programs will insist that a space bank that they use be official. This may be necessary for correct function of those programs. The space banks provided by the Gnosis system are official and obey commands to create new space banks that are also official.

Primordial space banks are available to the user and it is possible for a user to create his own. It is possible to deny a program or set of programs access to any of the space banks that are provided by the system. Thus it is possible to restrict a program or set of programs to a designated custom space bank for all new storage.

Such an intermediary can be used, for example, to ration pages, sell pages, lease or rent them, or otherwise administer a storage utilization policy. The same goes for nodes.

Pages and nodes may be returned to the bank for recycling. In particular; page keys and node keys may be presented for the purposes of deleting {recycling} the related page or node. The space bank can nullify all keys to a given page or node, effectively deleting the page. {(p2,sever)}

The space bank is in a position to institute policies that segregate some classes of storage on special real-storage devices. For instance, if it were felt desirable to put one customer's storage on an especially reliable type of disk, that customer would be given access to a space bank that would allocate space there. Other storage attributes might also be the grounds for segregation, such as physical backup, speed, busyness {access conflicts}, etc. Perhaps the space bank can be responsible for the arrangement of data to enable the 3850 {mass storage device} to operate efficiently. Special precautions are required here to group data that are used together into “disk pages” of 8 cylinders. The same problems with locality of reference occur with disk pages as with core pages. There would be two types of control: explicit and implicit. The explicit control would involve calls to the space bank to allocate a disk page {8 cylinders} and subsequently to allocate core pages from those 8 cylinders. Implicit control would consist of allocating pages for a given user in the same disk page insofar as possible.

See (p3,dest-bank) for a relevant convention.

The Space Bank and Space Bank Keys

A space bank has a page limit and a node limit {which may be used to restrict the amount of material that may be acquired form the bank}. 0 <= limit < 2**32. A limit is decreased when the bank creates a page or node and it is increased when it destroys a page or node.

Some keys to space banks have destroy rights. Some keys to space banks have query rights. Some keys to space banks have rights to change the limits.

There is an association between pages or nodes that have been acquired from a bank more recently than they have been returned. A page nor node that associated in this manner to a bank is said to be “acceptable” to the bank. A page or node created by a bank is acceptable to that bank. In the future it may be that other pages and nodes are not acceptable {(crl-fix)}.

Space Bank Transformer

{arcane}{nonref}Design notes