31-07-2014, 11:16 AM
Storage Management
[attachment=66409]
INTRODUCTION
storage is often a scare resource in a computing system.
storage management is one of the central concern of the programmer, language implementor , and language designer.
programming language design is strongly influenced by storage management considerations
storage management is one of the first concerns of the language implementor as well. while each language design permits the use of certain storage management techniques.
the implementor must choose or design one appropriate to the available hardware and software.
for example designing garbage collection in LISP.
typically languages contains many features or restrictions to allow one or another storage management teqnique to be used.
for example the restriction for FORTRAN to nonrecursive program.
PASCAL is carefully designed to allow stack based storagemanagement.
LISP to allow garbage collection.
the programmer is deeply concerned whit storage management ,but his position is somewhat anomalous.
When programmer design programs use storage efficiently by direct control over storage management.
it is often difficult for a programmer to discover what storage management techniques are actually used.
operation that may require storage to be allocated or freed .
1.subprograms call and return operations :
the execution of a subprogram return operation usually requires freeing of the storage allocated during the call.
2.data structure creation and destruction operations :
Pascal NEW operation , PL/I ALLOCATE operation .
the Pascal DISPOSE and the PL/I FREE operation.
Region allocation:
Initial storage structure:
FBQE (free block queue elements):
-The number of bytes in the free block. -Backward pointer to the preceding control back on the FBQE chain. -Forward pointer to the next control block on the FBQE chain.
Storage assignment
Dynamic method
Virtual storage:
is an advanced storage management technique that permit an extended address space consisting of real main storage and direct-address storage.
the basic element of virtual storage is page, a fixed-size unit of storage that is easily managed.
typical page size are 2048 or 4096 bytes.
NEED FOR HEAP STORAGE MANAGEMENT
The need for heap storage arises when a language require storage to be allocated and freed at arbitrary points during program execution .
For example :
# Concatenation in SNOBOL4
# Append an element to array in LISP
[attachment=66409]
INTRODUCTION
storage is often a scare resource in a computing system.
storage management is one of the central concern of the programmer, language implementor , and language designer.
programming language design is strongly influenced by storage management considerations
storage management is one of the first concerns of the language implementor as well. while each language design permits the use of certain storage management techniques.
the implementor must choose or design one appropriate to the available hardware and software.
for example designing garbage collection in LISP.
typically languages contains many features or restrictions to allow one or another storage management teqnique to be used.
for example the restriction for FORTRAN to nonrecursive program.
PASCAL is carefully designed to allow stack based storagemanagement.
LISP to allow garbage collection.
the programmer is deeply concerned whit storage management ,but his position is somewhat anomalous.
When programmer design programs use storage efficiently by direct control over storage management.
it is often difficult for a programmer to discover what storage management techniques are actually used.
operation that may require storage to be allocated or freed .
1.subprograms call and return operations :
the execution of a subprogram return operation usually requires freeing of the storage allocated during the call.
2.data structure creation and destruction operations :
Pascal NEW operation , PL/I ALLOCATE operation .
the Pascal DISPOSE and the PL/I FREE operation.
Region allocation:
Initial storage structure:
FBQE (free block queue elements):
-The number of bytes in the free block. -Backward pointer to the preceding control back on the FBQE chain. -Forward pointer to the next control block on the FBQE chain.
Storage assignment
Dynamic method
Virtual storage:
is an advanced storage management technique that permit an extended address space consisting of real main storage and direct-address storage.
the basic element of virtual storage is page, a fixed-size unit of storage that is easily managed.
typical page size are 2048 or 4096 bytes.
NEED FOR HEAP STORAGE MANAGEMENT
The need for heap storage arises when a language require storage to be allocated and freed at arbitrary points during program execution .
For example :
# Concatenation in SNOBOL4
# Append an element to array in LISP