In The Itanium And PA-RISC Architectures
(Die Seite wurde neu angelegt: „<br>Memory protection is a means to regulate memory entry rights on a computer, and is a part of most modern instruction set architectures and operating techni…“) |
K |
||
| Zeile 1: | Zeile 1: | ||
| − | <br>Memory | + | <br>Memory safety is a method to manage memory access rights on a computer, and is a part of most modern instruction set architectures and working systems. The main objective of memory safety is to stop a course of from accessing memory that has not been allotted to it. This prevents a bug or malware inside a process from affecting different processes, or the working system itself. Safety may encompass all accesses to a specified space of memory, write accesses, or makes an attempt to execute the contents of the world. Memory protection for computer security includes further techniques resembling tackle area structure randomization and executable-area protection. Segmentation refers to dividing a pc's memory into segments. A reference to a memory location consists of a value that identifies a section and an offset inside that section. A segment descriptor may limit access rights, e.g., read solely, only from sure rings. The x86 architecture has a number of segmentation options, that are useful for utilizing protected memory on this architecture.<br><br><br><br>On the x86 architecture, the global Descriptor Desk and local Descriptor Tables can be used to reference segments in the pc's memory. Pointers to [http://jicc.kr/bbs/board.php?bo_table=hosung3&wr_id=688410 Memory Wave] segments on x86 processors may also be saved in the processor's section registers. Initially x86 processors had four phase registers, CS (code segment), SS (stack phase), DS (data phase) and ES (extra segment); later one other two phase registers had been added - FS and GS. Using digital memory hardware, every web page can reside in any location at a suitable boundary of the pc's bodily memory, or be flagged as being protected. Digital memory makes it possible to have a linear digital memory tackle area and to make use of it to access blocks fragmented over physical memory deal with house. Most computer architectures which support paging [https://www.theepochtimes.com/n3/search/?q=additionally additionally] use pages as the idea for memory protection. A web page table maps digital memory to physical memory. There may be a single web page table, a web page table for every process, a web page table for each section, or a hierarchy of page tables, depending on the architecture and the OS.<br><br><br><br>The page tables are usually invisible to the process. Web page tables make it simpler to allocate further memory, as every new web page can be allocated from anyplace in bodily memory. On some techniques a page desk entry may also designate a web page as read-only. Some operating techniques set up a different handle space for each process, which offers laborious memory safety boundaries. Unallocated pages, and pages allocated to any other software, wouldn't have any addresses from the appliance viewpoint. A page fault could not necessarily point out an error. Web page faults aren't only used for memory protection. The working system intercepts the web page fault, masses the required memory web page, and the applying continues as if no fault had occurred. This scheme, a kind of virtual [http://jimiantech.com/g5/bbs/board.php?bo_table=w0dace2gxo&wr_id=397716 Memory Wave], permits in-memory knowledge not at the moment in use to be moved to secondary storage and back in a approach which is transparent to functions, to increase general memory capacity.<br><br><br><br>On some methods, a request for virtual storage could allocate a block of virtual addresses for which no page frames have been assigned, and the system will only assign and initialize web page frames when page faults happen. On some methods a guard page could also be used, either for error detection or to routinely grow knowledge structures. Each process also has a protection key worth related to it. On a memory entry the hardware checks that the present course of's safety key matches the value associated with the [https://safeareamain.com/bbs/board.php?bo_table=free&wr_id=81440 Memory Wave memory booster] block being accessed; if not, an exception happens. This mechanism was launched in the System/360 structure. It is accessible on immediately's System z mainframes and closely utilized by System z working systems and their subsystems. The System/360 protection keys described above are related to bodily addresses. That is completely different from the safety key mechanism used by architectures such as the Hewlett-Packard/Intel IA-sixty four and Hewlett-Packard PA-RISC, which are related to digital addresses, and which permit a number of keys per process.<br> |
Aktuelle Version vom 18. Oktober 2025, 13:19 Uhr
Memory safety is a method to manage memory access rights on a computer, and is a part of most modern instruction set architectures and working systems. The main objective of memory safety is to stop a course of from accessing memory that has not been allotted to it. This prevents a bug or malware inside a process from affecting different processes, or the working system itself. Safety may encompass all accesses to a specified space of memory, write accesses, or makes an attempt to execute the contents of the world. Memory protection for computer security includes further techniques resembling tackle area structure randomization and executable-area protection. Segmentation refers to dividing a pc's memory into segments. A reference to a memory location consists of a value that identifies a section and an offset inside that section. A segment descriptor may limit access rights, e.g., read solely, only from sure rings. The x86 architecture has a number of segmentation options, that are useful for utilizing protected memory on this architecture.
On the x86 architecture, the global Descriptor Desk and local Descriptor Tables can be used to reference segments in the pc's memory. Pointers to Memory Wave segments on x86 processors may also be saved in the processor's section registers. Initially x86 processors had four phase registers, CS (code segment), SS (stack phase), DS (data phase) and ES (extra segment); later one other two phase registers had been added - FS and GS. Using digital memory hardware, every web page can reside in any location at a suitable boundary of the pc's bodily memory, or be flagged as being protected. Digital memory makes it possible to have a linear digital memory tackle area and to make use of it to access blocks fragmented over physical memory deal with house. Most computer architectures which support paging additionally use pages as the idea for memory protection. A web page table maps digital memory to physical memory. There may be a single web page table, a web page table for every process, a web page table for each section, or a hierarchy of page tables, depending on the architecture and the OS.
The page tables are usually invisible to the process. Web page tables make it simpler to allocate further memory, as every new web page can be allocated from anyplace in bodily memory. On some techniques a page desk entry may also designate a web page as read-only. Some operating techniques set up a different handle space for each process, which offers laborious memory safety boundaries. Unallocated pages, and pages allocated to any other software, wouldn't have any addresses from the appliance viewpoint. A page fault could not necessarily point out an error. Web page faults aren't only used for memory protection. The working system intercepts the web page fault, masses the required memory web page, and the applying continues as if no fault had occurred. This scheme, a kind of virtual Memory Wave, permits in-memory knowledge not at the moment in use to be moved to secondary storage and back in a approach which is transparent to functions, to increase general memory capacity.
On some methods, a request for virtual storage could allocate a block of virtual addresses for which no page frames have been assigned, and the system will only assign and initialize web page frames when page faults happen. On some methods a guard page could also be used, either for error detection or to routinely grow knowledge structures. Each process also has a protection key worth related to it. On a memory entry the hardware checks that the present course of's safety key matches the value associated with the Memory Wave memory booster block being accessed; if not, an exception happens. This mechanism was launched in the System/360 structure. It is accessible on immediately's System z mainframes and closely utilized by System z working systems and their subsystems. The System/360 protection keys described above are related to bodily addresses. That is completely different from the safety key mechanism used by architectures such as the Hewlett-Packard/Intel IA-sixty four and Hewlett-Packard PA-RISC, which are related to digital addresses, and which permit a number of keys per process.