NetWare 4.1/9000 Concepts

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NetWare Glossary
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The 8086 processor uses a 20-bit address bus, and can address up to 1 MB of
memory. The 8086 processor is also limited to running only one application
or process at a time.
When running in protected mode, the 80286, 80386, and 80486 processors
are capable of multitasking and addressing much more than 1 MB of
memory.
When running in real mode, these processors are subject to the same 1MB
memory constraint as the 8086 processor, and they can run only one
application or process at a time.
However, the 80286, 80386, and 80486 processors running in real mode
perform more efficiently than the 8086 processor, because they operate at a
faster clock rate.
See also “Protected mode.”
Record locking
A feature that prevents different users from gaining simultaneous access to
the same record in a shared file, preventing overlapping disk writes and
ensuring data integrity. A physical record lock—also called a byte-range
lock—locks a specific byte range within a file; a logical record lock locks a
record name associated with one or more files and/or records.
NetWare uses a physical record lock to control data access by multiple users.
When a client requests access to the data, the application requests a physical
lock on a byte range in the file. The Lock Manager records this byte range in
its lock table and enforces the lock. NetWare Services enforces physical
locks for all NetWare clients.
An application or client uses a logical record lock to control access by
multiple users. The application assigns a name to each resource that needs to
be locked so that only one user can access the resource. A logical record
name is also referred to as a synchronization string. Logical record locking
does not lock the data represented by the string; it only locks the string itself.
See also “File locking”; “nwcm”; “Synchronization services”; “UNIX host
locking.”