Booting Up 15-Nov-18 boot.ppt

first 64K computer address space what is in a PC’s memory when the computer is off? most of RAM is empty when the PC first powers up RAM is volatile because its contents are lost when power goes off but, two small parts are different read-only non-volatile EEPROM (contains code) 0 8K 16K 24K 32K 40K 48K 56K 64K RAM battery-backed RAM (contains hardware settings) when the PC first powers up, where is the operating system? 15-Nov-18 boot.ppt

battery-backed RAM battery-backed RAM contains a simple database also called the CMOS a program called “Setup” is used to modify it you can start Setup only while booting the computer its data describes hardware parameters time/date what disk drives are present what kind of display is present how much memory is present how fast some components should run etc. 0 8K 16K 24K 32K 40K 48K 56K 64K RAM EEPROM (contains code) battery-backed RAM (contains hardware settings) how does the configuration data get modified? plug and play devices the Setup program 15-Nov-18 boot.ppt

the EEPROM the EEPROM contains the programs needed to start the computer also called the BIOS, or the firmware because it contains only programs, it can be read-only: BIOS routines (a minimal keyboard/display driver) POST routines (e.g., RAM parity check, keyboard test) setup program – lets users view or modify hardware settings bootstrap program – searches disk drives for an operating system 0 8K 16K 24K 32K 40K 48K 56K 64K RAM EEPROM (contains code) battery-backed RAM (contains hardware settings) how does the BIOS get updated if its programs need to change? 15-Nov-18 boot.ppt

add-on boards also contain BIOS chips the motherboard BIOS contains code to access the keyboard, floppy drive, ATA (IDE) hard disk controllers, USB devices, and disk drives a computer system can contain several BIOS firmware chips plug-in adapter cards such as network interface cards and video boards often include their own BIOS complementing or replace the system BIOS code for the given component CMOS (“Setup”) database maps these extra BIOS programs into the low memory address space 15-Nov-18 boot.ppt

what is a disk drive? a piece of physical hardware non-volatile storage programs on a disk drive must be loaded into RAM before they execute disk drives must be subdivided into partitions the act of writing on a disk drive to partition it is called partitioning you have to know which OS will use the partition before you create it partitions have to be formatted with a particular file system typically, each OS uses a different file system PC partitions have one or more logical drive letters associated with them Solaris partitions have directories associated with them (“mounted”) 15-Nov-18 boot.ppt

more about disk drives what is fdisk? a utility from Microsoft for partitioning disks part of the original DOS 6.x operating system a more versatile utility: Partition Magic what is a boot sector? (master boot record, or MBR) the first accessible “sector” on a drive it contains: a table of (up to 4) partitions optionally, code to bootstrap an OS from the “active” partition the partition table in the boot sector contains up to 4 entries: primary partition takes up one entry in partition table, and contains a single logical drive extended partition takes up 1 entry in partition table, and may contain multiple DOS, Linux or other partitions (logical drives in Windows) Solaris partition takes up 1 entry in partition table active partition a primary partition that is bootable 15-Nov-18 boot.ppt

starting Windows on an x86-based computer since 1981, all x86-based computers use the partition style known as the master boot record (MBR) first used by MS-DOS in 1981, and continued up through Windows XP Pro when you start your computer, the first code that executes is the BIOS BIOS loads the bytes from the MBR of the boot device into memory it then transfers control to the bytes just loaded into memory the MBR’s first bytes are code to start loading the operating system but first, it has to find the operating system It looks that up in the partition table (stored in the end of the MBR) Because MBR is the only partition style available on x86-based computers running Windows XP or earlier, it is used automatically and you do not need to choose this style Dynamic disks were introduced in Windows 2000 and they provide features that basic disks do not, such as the ability to create volumes that span multiple disks, including fault-tolerant mirrored and RAID-5 volumes. Requires a GPT partition style GPT stands for “GUID Partition Table” GUID stands for “Globally Unique ID” 15-Nov-18 boot.ppt

MBR the first physical sector on a disk contains a data structure known as the Master Boot Record (MBR). The MBR contains the following: a boot program (up to 442 bytes in size) a disk signature (a unique 4-byte number) a partition table (up to four entries) an end-of-MBR marker (always 0x55AA) 15-Nov-18 boot.ppt

enter GPT partitions and EFI Extensible Firmware Interface (EFI) is a specification that defines a software interface between an operating system and platform firmware. EFI is intended as a significantly improved replacement of the old legacy BIOS firmware interface historically used by all IBM PC compatible personal computers the EFI specification was originally developed by Intel now managed by the Unified EFI Forum and is officially known as Unified EFI (UEFI) Used first on Itanium processor systems Also used by 64-bit Windows versions Vista can use them as data disks (but not boot drives) XP Pro cannot use them at all 15-Nov-18 boot.ppt

kinds of hard drives today basic MBR disk – Windows XP systems all use this basic GPT disk dynamic MBR disk dynamic GPT disk if using EFI, there also has to be a special partition containing the particular EFI code your computer system happens to need what are the implications of this? 15-Nov-18 boot.ppt

Boot Camp I have a MacBook capable of running both Mac OS X and Windows XP the laptop is 2 years old cost was $1200 + $300 for Windows XP Pro license it only has Mac OS 10.4, “Tiger” not 10.5, “Leopard”, the latest came with 512K, not enough memory to run Leopard how did I get it to run Windows? Mac OS 10.4 let me download a special program called Boot Camp it created a Windows partition, after which, I installed Windows XP Pro on that partition coupla years went by… recently, my Windows XP install partition got sick; I needed to restart Windows it died in a way that even Mac OS X was unable to redo the Windows partition so I also had to reinstall Mac OS X (10.4) Boot Camp was cripple-ware “expired”; could no longer download it what to do? 15-Nov-18 boot.ppt

the end of this slideset 15-Nov-18 boot.ppt

I have a MacBook with Apple’s “Boot Camp” program on it What does Boot Camp do? Can I just run Windows on my MacBook without 15-Nov-18 boot.ppt