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In a system using segmentation, computer memory addresses consist of a segment id and an offset within the segment. [3] A hardware memory management unit (MMU) is responsible for translating the segment and offset into a physical address, and for performing checks to make sure the translation can be done and that the reference to that segment and offset is permitted.
Flat memory model or linear memory model refers to a memory addressing paradigm in which "memory appears to the program as a single contiguous address space." [ 1 ] The CPU can directly (and linearly ) address all of the available memory locations without having to resort to any sort of bank switching , memory segmentation or paging schemes.
The memory model concept derives from the setup of the segment registers. For example, in the tiny model CS=DS=SS, that is the program's code, data, and stack are all contained within a single 64 KB segment. In the small memory model DS=SS, so both data and stack reside in the same segment; CS points to a different code segment of up to 64 KB.
A closed line segment includes both endpoints, while an open line segment excludes both endpoints; a half-open line segment includes exactly one of the endpoints. In geometry , a line segment is often denoted using an overline ( vinculum ) above the symbols for the two endpoints, such as in AB .
DS (data segment), CS (code segment), SS (stack segment), and ES (extra segment). Another 16-bit register can act as an offset into a given segment, and so a logical address on this platform is written segment:offset, typically in hexadecimal notation. In real mode, in order to calculate the physical address of a byte of memory, the hardware ...
In some operating systems, a task is synonymous with a process, in others with a thread. In batch processing computer systems, a task is a unit of execution within a job. The system user of μC/OS-II is able to control the tasks by using the following features: Task feature; Task creation; Task stack & stack checking; Task deletion; Change a ...
The JSON Meta Application Protocol (JMAP) is a set of related open Internet Standard protocols for handling email. JMAP is implemented using JSON APIs over HTTP and has been developed as an alternative to IMAP / SMTP and proprietary email APIs such as Google's Gmail and Microsoft's MAPI (used by Outlook). [ 1 ]
The GDT is a table of 8-byte entries. Each entry may refer to a segment descriptor, Task State Segment (TSS), Local Descriptor Table (LDT), or call gate. Call gates were designed for transferring control between x86 privilege levels, although this mechanism is not used on most modern operating systems. There is also a Local Descriptor Table (LDT).