CPU Sockets, POST & Boot Process PDF

CPU Sockets, POST and the Boot Process CST8208 Features of Modern CPUs  Some features to consider when choosing a processor: Entry level/mainstream/high end Hardware virtualization support Multiple cores Amount of cache memory (L3 cache) Hyper-thre...

CPU Sockets, POST and the Boot Process CST8208 Features of Modern CPUs  Some features to consider when choosing a processor: Entry level/mainstream/high end Hardware virtualization support Multiple cores Amount of cache memory (L3 cache) Hyper-threading Turbo Boost Features of Modern CPUs  Entry level/mainstream/high end Typically i3, i5 and i7/i9 categories Features vary from generation to generation (such as number of cores as well as availability of turbo boost and hyper threading)  Hardware virtualization Most recent processors have hardware virtualization capabilities (ex. Intel’s VT-x) that allow the processor to reserve resources at the hardware level for individual virtual machines Features of Modern CPUs  Multiple Cores Most modern CPUs have multiple processor cores allowing it to effectively work like it has multiple processors Can have 2, 4, 6 or more cores  Cache memory Higher end processors usually have more L3 cache than lower end processors (ex. An i3 processor might have 2-4 MB while an i7 of the same generation might have 6-8 MB) Features of Modern CPUs  Hyper Threading Allows the processor to appear to the OS and compatible software has having twice as many cores as it actually does Each core can run two processing threads simultaneously Not as powerful as having twice as many physical cores, but still provides significant performance improvements over a single core/single thread Features of Modern CPUs  Turbo Boost A feature available in many recent processors that allow the processor to run at speeds above the processor’s standard speed. Used only when under demanding load, and only when below power and thermal thresholds Typically one or some cores in a multicore processor will perform faster with turbo boost, but not usually all of them Desktop Sockets  Intel Socket LGA 775 (T) Socket LGA 1366 (B) Socket LGA 1156 (H1), 1155 (H2), 1150 (H3) and 1151 (H4)  AMD Socket AM2/AM2+, AM3/AM3+, AM4 Socket FM, FM2  POST  The Power-On Self-Test checks for the presence of hardware devices and their functionality  You’ll often hear the HDD spin up, the lights on the keyboard will blink, and circuitry and chipsets are checked as well  If a serious fault or error is found, the system is halted. Most typical errors are expressed as a beep code or error message  Serious faults and errors can be better diagnosed with a POST card Booting A Computer  With the exception of the data stored in the CMOS, the computer has no recollection of what devices are attached to it or how to address them  Each time your computer is booted or rebooted, it has to learn it’s contents all over again The BIOS Startup Screen  A lot of vital information about a system can be gathered from this screen as it usually displays: Motherboard manufacturer and model BIOS manufacturer, version number/date and serial number Prompt to enter setup program Processor make and model (and sometimes speed as configured) Type and amount of memory Cold Boot (Hard Reset)  A cold boot occurs when the system has been completely turned off and turned back on again. In this case, it has to complete the entire boot process again  All functions of the computer are interrupted and can cause serious problems if it happens during a saving/writing process  Also occurs when power is interrupted and the OS isn’t properly shut down Warm Boot (Soft Reboot)  A warm boot occurs when a system is already running and is properly reset using menu options or commands from within an operating system.  Can also invoked with Alt-Ctrl-Del key combination on most systems  On a warm boot, the POST process is not run (at least not in it’s entirety) Steps in the Boot Process  1. The power supply is started. It can take half a second to generate the voltages necessary to run the system. The power good signal is sent by the power supply.  2. The CPU is initialized and reset. If it’s a multi- processor system or a multi-core processor, one CPU or core is randomly chosen to start the system.  3. CPU starts the system ROM BIOS bootstrap loader  4. BIOS programs are loaded into main memory (process called “shadowing”) Steps in the Boot Process  5. The BIOS begins to check hardware configuration and gives beep codes should any checks fail  6. Video ROM is initialized and, if successful, begins to display information on the monitor  7. Any other device ROMs are started (network adapter, hard drive, DVD drive, etc) Steps in the Boot Process  8. BIOS begins a number of test routines such as memory count and further hardware confirmation, and can now display a variety of error codes if need be  9. The expansion busses are checked and any plug and play devices are detected and assigned resources. This information is checked against the ESCD (Extended System Configuration Data) stored in the CMOS Steps in the Boot Process  10. Information about the devices is displayed and indicates if new hardware has been found  11. Chooses a boot device based on order specified in CMOS (optical drive, hard drive, USB, etc) looking for a boot record and proceeds to load the OS