INT 19 - SYSTEM - BOOTSTRAP LOADER Desc: This interrupt reboots the system without clearing memory or restoring interrupt vectors. Because interrupt vectors are preserved, this interrupt usually causes a system hang if any TSRs have hooked vectors from 00h through 1Ch, particularly INT 08. Notes: Usually, the BIOS(Basic Input/Output System) A set of standardized calls giving low-level access to the hardware. The BIOS is the lowest software layer above the actual hardware and serves to insulate programs (and operating systems) which use it from the details of accessing the hardware directly. will try to read sector 1, head 0, track 0 from drive A: to 0000h:7C00h. If this fails, and a hard disk is installed, the BIOS(Basic Input/Output System) A set of standardized calls giving low-level access to the hardware. The BIOS is the lowest software layer above the actual hardware and serves to insulate programs (and operating systems) which use it from the details of accessing the hardware directly. will read sector 1, head 0, track 0 of the first hard disk. This sector should contain a master bootstrap loader and a partition table (see #00650). After loading the master boot sector at 0000h:7C00h, the master bootstrap loader is given control (see #00653). It will scan the partition table for an active partition, and will then load the operating system's bootstrap loader (contained in the first sector of the active partition) and give it control. true IBMInternational Busiuness MachinesInternational Busiuness Machines) A hardware, software and other service technology company founded in 1911. PCs and most clones issue an INT 18 if neither floppy nor hard disk have a valid boot sector to accomplish a warm boot equivalent to Ctrl-Alt-Del, store 1234h in 0040h:0072h and jump to FFFFh:0000h. For a cold boot equivalent to a reset, store 0000h at 0040h:0072h before jumping. VDISK.SYS hooks this interrupt to allow applications to find out how much extended memory has been used by VDISKs (see #00649). DOS 3.3+ PRINT hooks INT 19 but does not set up a correct VDISK header block at the beginning of its INT 19 handler segment, thus causing some programs to overwrite extended memory which is already in use. the default handler is at F000h:E6F2h for 100% compatible BIOSes MS-DOS 3.2+ hangs on booting (even from floppy) if the hard disk contains extended partitions which point at each other in a loop, since it will never find the end of the linked list of extended partitions under Windows Real and Enhanced modes, calling INT 19 will hang the system in the same was as under bare DOS; under Windows Standard mode, INT 19 will successfully perform a cold reboot as it appears to have been redirected to a MOV AL,0FEh/OUT 64h,AL sequence BUG: when loading the remainder of the DOS system files fails, various versions of IBMBIO.COM/IO.SYS incorrectly restore INT 1E before calling INT 19, assuming that the boot sector had stored the contents of INT 1E at DS:SI instead of on the stack as it actually does SeeAlso: INT 14/AH=17h,INT 18"BOOT HOOK",INT 49"Tandy 2000",INT 5B"PCIBM PC Cluster" SeeAlso: MEM 0040h:0067h,MEM F000h:FFF0h,CMOS(Complementary Metal-Oxide-Semiconductor) A type of integrated circuit design known for its low power consumption. 0Fh Format of VDISK header block (at beginning of INT 19 handler's segment): Offset Size Description (Table 00649) 00h 18 BYTEs n/a (for VDISK.SYS, the device driver header) 12h 11 BYTEs signature string "VDISK Vn.m" for VDISK.SYS version n.m 1Dh 15 BYTEs n/a 2Ch 3 BYTEs linear address of first byte of available extended memory Format of hard disk master boot sector: Offset Size Description (Table 00650) 00h 446 BYTEs Master bootstrap loader code 1BEh 16 BYTEs partition record for partition 1 (see #00651) 1CEh 16 BYTEs partition record for partition 2 1DEh 16 BYTEs partition record for partition 3 1EEh 16 BYTEs partition record for partition 4 1FEh WORD signature, AA55h indicates valid boot block Format of partition record: Offset Size Description (Table 00651) 00h BYTE boot indicator (80h = active partition) 01h BYTE partition start head 02h BYTE partition start sector (bits 0-5) 03h BYTE partition start track (bits 8,9 in bits 6,7 of sector) 04h BYTE operating system indicator (see #00652) 05h BYTE partition end head 06h BYTE partition end sector (bits 0-5) 07h BYTE partition end track (bits 8,9 in bits 6,7 of sector) 08h DWORDDoubleword; four bytes. Commonly used to hold a 32-bit segment:offset or selector:offset address. sectors preceding partition 0Ch DWORDDoubleword; four bytes. Commonly used to hold a 32-bit segment:offset or selector:offset address. length of partition in sectors SeeAlso: #00650 (Table 00652) Values for operating system indicator: 00h empty partition-table entry 01h DOS 12-bit FATsee File Allocation Table 02h XENIX root file system 03h XENIX /usr file system (obsolete) 04h DOS 16-bit FATsee File Allocation Table (up to 32M) 05h DOS 3.3+ extended partition 06h DOS 3.31+ Large File System (16-bit FATsee File Allocation Table, over 32M) 07h QNX 07h OS/2 HPFS 07h Windows NT NTFS 07h Advanced Unix 07h see partition boot record; could be any of the above or others 08h OS/2 (v1.0-1.3 only) 08h AIX bootable partition, SplitDrive 08h Commodore DOS 08h DELL partition spanning multiple drives 09h AIX data partition 09h Coherent filesystem 0Ah OS/2 BootTo start up the computer or operating system. The term "boot" is a contraction of "bootstrap", which in turn comes from the expression "to lift oneself by one's boot straps." The ROM BIOS on IBMInternational Busiuness Machines PCs and compatibles reads in the first sector of the disk, which contains a short (less than 500 bytes) program that reads in a portion of the operating system, which in turn reads in the remainder of the operating system. See also IPL. Manager 0Ah OPUS 0Ah Coherent swap partition 0Bh Windows95 with 32-bit FATsee File Allocation Table 0Ch Windows95 with 32-bit FATsee File Allocation Table (using LBA-mode INT 13 extensions) 0Eh logical-block-addressable VFAT (same as 06h but using LBA-mode INT 13) 0Fh logical-block-addressable VFAT (same as 05h but using LBA-mode INT 13) 10h OPUS 11h OS/2 BootTo start up the computer or operating system. The term "boot" is a contraction of "bootstrap", which in turn comes from the expression "to lift oneself by one's boot straps." The ROM BIOS on IBMInternational Busiuness Machines PCs and compatibles reads in the first sector of the disk, which contains a short (less than 500 bytes) program that reads in a portion of the operating system, which in turn reads in the remainder of the operating system. See also IPL. Manager hidden 12-bit FATsee File Allocation Table partition 12h Compaq Diagnostics partition 14h (resulted from using Novell DOS 7.0 FDISK to delete Linux Native part) 14h OS/2 BootTo start up the computer or operating system. The term "boot" is a contraction of "bootstrap", which in turn comes from the expression "to lift oneself by one's boot straps." The ROM BIOS on IBMInternational Busiuness Machines PCs and compatibles reads in the first sector of the disk, which contains a short (less than 500 bytes) program that reads in a portion of the operating system, which in turn reads in the remainder of the operating system. See also IPL. Manager hidden sub-32M 16-bit FATsee File Allocation Table partition 16h OS/2 BootTo start up the computer or operating system. The term "boot" is a contraction of "bootstrap", which in turn comes from the expression "to lift oneself by one's boot straps." The ROM BIOS on IBMInternational Busiuness Machines PCs and compatibles reads in the first sector of the disk, which contains a short (less than 500 bytes) program that reads in a portion of the operating system, which in turn reads in the remainder of the operating system. See also IPL. Manager hidden over-32M 16-bit FATsee File Allocation Table partition 17h OS/2 BootTo start up the computer or operating system. The term "boot" is a contraction of "bootstrap", which in turn comes from the expression "to lift oneself by one's boot straps." The ROM BIOS on IBMInternational Busiuness Machines PCs and compatibles reads in the first sector of the disk, which contains a short (less than 500 bytes) program that reads in a portion of the operating system, which in turn reads in the remainder of the operating system. See also IPL. Manager hidden HPFS partition 17h hidden NTFS partition 18h AST special Windows swap file ("Zero-Volt Suspend" partition) 19h Willowtech Photon coS 1Bh hidden Windows95 FAT32 partition 1Ch hidden Windows95 FAT32 partition (using LBA-mode INT 13 extensions) 1Eh hidden LBA VFAT partition 20h Willowsoft Overture File System (OFS1) 21h officially listed as reserved 21h FSo2 23h officially listed as reserved 24h NEC MS-DOS 3.x 26h officially listed as reserved 31h officially listed as reserved 33h officially listed as reserved 34h officially listed as reserved 36h officially listed as reserved 38h Theos 3Ch PowerQuest PartitionMagic recovery partition 40h VENIX 80286 41h Personal RISC BootTo start up the computer or operating system. The term "boot" is a contraction of "bootstrap", which in turn comes from the expression "to lift oneself by one's boot straps." The ROM BIOS on IBMInternational Busiuness Machines PCs and compatibles reads in the first sector of the disk, which contains a short (less than 500 bytes) program that reads in a portion of the operating system, which in turn reads in the remainder of the operating system. See also IPL. 41h PowerPC boot partition 42h SFS (Secure File System) by Peter Gutmann 45h EUMEL/Elan 46h EUMEL/Elan 47h EUMEL/Elan 48h EUMEL/Elan 4Fh Oberon boot/data partition 50h OnTrack Disk Manager, read-only partition 51h OnTrack Disk Manager, read/write partition 51h NOVELL 52h CP/M(Control Program for Microcomputers) An early operating system for micros based on the 8-bit Intel 8080 CPU (and later the compatible 8085 and Zilog Z80 CPUs). MSDOS version 1.0 was essentially a clone of CP/M for the Intel 8086. 52h Microport System V/386 53h OnTrack Disk Manager, write-only partition??? 54h OnTrack Disk Manager (DDO) 55h EZ-Drive (see also INT 13/AH=FFh"EZ-Drive") 56h GoldenBow VFeature 5Ch Priam EDISK 61h SpeedStor 63h Unix SysV/386, 386/ix 63h Mach, MtXinu BSD 4.3 on Mach 63h GNU HURD 64h Novell NetWare 286 64h SpeedStore 65h Novell NetWare (3.11) 67h Novell 68h Novell 69h Novell 70h DiskSecure Multi-Boot 71h officially listed as reserved 73h officially listed as reserved 74h officially listed as reserved 75h PCIBM PC/IX 76h officially listed as reserved 7Eh F.I.X. 80h Minix v1.1 - 1.4a 81h Minix v1.4b+ 81h Linux 81h Mitac Advanced Disk Manager 82h Linux Swap partition 82h Prime 82h Solaris (Unix) 83h Linux native file system (ext2fs/xiafs) 84h OS/2-renumbered type 04h partition (related to hiding DOS C: drive) 85h Linux EXT 86h FAT16 volume/stripe set (Windows NT) 87h HPFS Fault-Tolerant mirrored partition 87h NTFS volume/stripe set 93h Amoeba file system 94h Amoeba bad block table 98h Datalight ROM-DOS SuperBoot 99h Mylex EISA(Enhanced Industry-Standard Architecture) A 32-bit superset of the IBMInternational Busiuness Machines ATIBM PC AT's expansion bus (which is now known as the ISA or Industry-Standard Architecture bus). SCSI(Small Computer Systems Interface) A system-independent expansion bus typically used to connect hard disks, tape drives, and CD-ROMs to a computer. A host adapter connects the SCSI bus to the computer's own bus. See also ESDI, IDE. A0h Phoenix NoteBIOS Power Management "Save-to-Disk" partition A1h officially listed as reserved A3h officially listed as reserved A4h officially listed as reserved A5h FreeBSD, BSD/386 A6h OpenBSD A9h NetBSD (http://www.netbsd.org/) B1h officially listed as reserved B3h officially listed as reserved B4h officially listed as reserved B6h officially listed as reserved B6h Windows NT mirror set (master), FAT16 file system B7h BSDI file system (secondarily swap) B7h Windows NT mirror set (master), NTFS file system B8h BSDI swap partition (secondarily file system) BEh Solaris boot partition C0h DR DOS/DR-DOS/Novell DOS secured partition C0h CTOS C1h DR DOS 6.0 LOGIN.EXE-secured 12-bit FATsee File Allocation Table partition C4h DR DOS 6.0 LOGIN.EXE-secured 16-bit FATsee File Allocation Table partition C6h DR DOS 6.0 LOGIN.EXE-secured Huge partition C6h corrupted FAT16 volume/stripe set (Windows NT) C6h Windows NT mirror set (slave), FAT16 file system C7h Syrinx BootTo start up the computer or operating system. The term "boot" is a contraction of "bootstrap", which in turn comes from the expression "to lift oneself by one's boot straps." The ROM BIOS on IBMInternational Busiuness Machines PCs and compatibles reads in the first sector of the disk, which contains a short (less than 500 bytes) program that reads in a portion of the operating system, which in turn reads in the remainder of the operating system. See also IPL. C7h corrupted NTFS volume/stripe set C7h Windows NT mirror set (slave), NTFS file system CBh Reserved for DR DOS/DR-DOS/OpenDOS secured FAT32 CCh Reserved for DR DOS/DR-DOS secured FAT32 (LBA) CEh Reserved for DR DOS/DR-DOS secured FAT16 (LBA) D0h Multiuser DOS secured FAT12 D1h Old Multiuser DOS secured FAT12 D4h Old Multiuser DOS secured FAT16 (<= 32M) D5h Old Multiuser DOS secured extended partition D6h Old Multiuser DOS secured FAT16 (> 32M) D8h CP/M-86One of the three operating systems offered by IBMInternational Busiuness Machines for its original PCIBM PC (the other two were MSDOS and the UCSD p-System). It has since evolved into DR-DOS version 6 and Novell DOS 7. DBh CP/M(Control Program for Microcomputers) An early operating system for micros based on the 8-bit Intel 8080 CPU (and later the compatible 8085 and Zilog Z80 CPUs). MSDOS version 1.0 was essentially a clone of CP/M for the Intel 8086., Concurrent CP/M(Control Program for Microcomputers) An early operating system for micros based on the 8-bit Intel 8080 CPU (and later the compatible 8085 and Zilog Z80 CPUs). MSDOS version 1.0 was essentially a clone of CP/M for the Intel 8086., Concurrent DOS DBh CTOS (Convergent Technologies OS) E1h SpeedStor 12-bit FATsee File Allocation Table extended partition E2h DOS read-only (Florian Painke's XFDISK 1.0.4) E3h DOS read-only E3h Storage Dimensions E4h SpeedStor 16-bit FATsee File Allocation Table extended partition E5h officially listed as reserved E6h officially listed as reserved EBh BeOS BFS (BFS1) F1h Storage Dimensions F2h DOS 3.3+ secondary partition F3h officially listed as reserved F4h SpeedStor F4h Storage Dimensions F5h Prologue F6h officially listed as reserved FEh LANstep FEh IBMInternational Busiuness MachinesInternational Busiuness Machines) A hardware, software and other service technology company founded in 1911. PS/2IBM PS/2, any model IML (Initial Microcode Load) partition FFh Xenix bad block table Note: for partition type 07h, one should inspect the partition boot record for the actual file system type SeeAlso: #00651 (Table 00653) Values Bootstrap loader is called with (IBMInternational Busiuness MachinesInternational Busiuness Machines) A hardware, software and other service technology company founded in 1911. BIOS(Basic Input/Output System) A set of standardized calls giving low-level access to the hardware. The BIOS is the lowest software layer above the actual hardware and serves to insulate programs (and operating systems) which use it from the details of accessing the hardware directly.): CS:IP(Internet Protocol) The lower level (transport layer) of the TCP/IP protocol suite. See also TCP, TCP/IP. = 0000h:7C00h DH = access bits 7-6,4-0: don't care bit 5: =0 device supported by INT 13 DL = boot drive 00h first floppy 80h first hard disk