Persistence

摘要： The operating system plays a key role in energy management. It controls all the devices, so itmust decide what to shutdown and when to shut it down. I... 阅读全文

摘要： The general approach most computer vendors take to battery conservation is to design the CPU,memory, and I/O devices to have multiple states: on, slee... 阅读全文

摘要： The first general-purpose electronic comuter, the ENIAC, had 18,000 vacuum tubes andconsumed 140,000 watts of power. As a result, it ran up a non-triv... 阅读全文

摘要： Over the years, the main computing paradigm has oscillated between centralized and decentralizedcomputing. The first computers, such as the ENIAC, wer... 阅读全文

摘要： Scheduling policy is a balancing act between competing goals. Modern scheduling policiesmake tradeoffs between three primary goals: fairness, low late... 阅读全文

摘要： In order to virtualize the CPU, the operating system needs to somehow share the physical CPUamong many jobs running seemingly at the same time. The ba... 阅读全文

摘要： Most personal computers offer a GUI (Graphical User Interface). The acronym GUI is pronounced ''gooey''.The GUI was invented by Douglas Engelbart and ... 阅读全文

摘要： Nearly all UNIX systems base their user interface on the X Window System (often called X),developed ar MIT as part of project Athena in the 1980s. It ... 阅读全文

摘要： Thus far, the way we have described how replacements occur assumes that the OS waits untilmemory is entirely full, and only then replaces or evicts a ... 阅读全文

摘要： Recall that with TLB misses, we have two types of systems: Hardware managed TLBs (where thehardware looks in the page table to find the desired transl... 阅读全文

摘要： Thus far, we have assumed that an address space is unrealistically small and fits into the physicalmemory. In fact, we have been assuming that every a... 阅读全文

摘要： We now tackle the second problem that paging introduces: page tables are too big and thus consumetoo much memory. Let us start out with a linear page ... 阅读全文

摘要： In order to virtualize the CPU, the operating system needs to somehow share the physicalCPU among many jobs running seemingly at the same time. The ba... 阅读全文

摘要： Aside: RTFM --- Read The Man PagesMany times in this book, when referring to a particular system call or library call, we willtell you to read the man... 阅读全文

摘要： All the clock hardware does is to generate interrupts at known intervals. Everythingelse involving time must be done by the software, the clock driver... 阅读全文