A CDAPEEK key allows the
holder to look at the backup version of any page or node
The backup version of a page or node is the version that would exist if the system restarted from the last checkpoint.
A Charge Set key gives the
holder access to KeyKOS's memory of which data a domain has accessed
recently. The charge set depicts a set of pages and nodes and
is used to measure the utilization of main storage and channels by a
domain.
A data key returns a non-negative
integer value. Data keys always return a specific non-zero return code
(x'80000001') so that domains are more likely to sense when a key they
hold designates a deleted object.
Device I/O keys are
created by BDEVICE and give the holder authority to issue restricted
channel programs for the device. The following restrictions are
enforced:
Data chaining, PCI, and indirect data address words may not be used.
Pages referenced must exist, even if SKIP is specified.
All but the last channel-control-word must specify command chaining; the
last must not.
Discrim provides a method
for obtaining basic information about keys. This information can be
gathered with much more difficulty using self-destructive or statistical
techniques.
A domain key grants its
holder the ability to extract and insert all data and keys that would be
available to a program running in the domain. It
also provides access to portions of the domain that are not automatically
available to programs running in the domain.
The error key is for emergency use by
domains "close" to the KeyKOS kernel. It is invoked when there
is an error condition that cannot be handled by any program outside the
kernel.
The journalize page key is invoked to
preserve the current data in a page across checkpoint restart. That is, the
checkpoint image of the page is updated to the current contents of the
page.
Keybits returns a bit pattern
for a key whose contents may change in new releases of KeyKOS and
whose interpretation is proprietary. The bit pattern returned for a particular
key is guaranteed to be the same for a particular version of KeyKOS.
A node key gives the holder the
authority to read and write keys in the node. A node key is also used to
create attenuated keys to the node, such as a fetch key and a meter key.
Range keys are the primary
tools of space banks. Each range key controls a definite set
of pages or nodes. A key that controls a set of pages is called a
page range key and a key that controls a
set of nodes is called a node range
key.
Returner returns information
passed to it. A domain is guaranteed never to stall invoking Returner,
which makes Returner a useful tool for domains that provide public
services and must return to their invokers without the possibility of
stalling on that return.
A sense key returns
sensory versions of keys. A sensory version of a key is a
key through which information can only flow toward the holder of
the key.