Operating Systems

• Real Time Operating Systems (RTOS) +
• MS-DOS or PC-DOS
  • Memory Maps
  • Services
  • Initialization
  • Listings
  • History
  • Device Drivers
  • Extenders
• UNIX / Linux
• Windows
  • 1
  • 3.1
  • 95
  • 98
  • NT
  • ME
  • XP (and XP mode in Windows 7)
  • 2K3 SBS: Windows Server 2003 Small Business +
  • 2K8 SBS: Windows Server 2008 Small Business Server (x64)
• VIrtual Box

PC's can be booted into many different operatings systems. The boot device is normally the hard drive, but for development, portability, and experiminatation, booting from a USB flash drive is ideal. See:

• http://www.easy2boot.com/make-an-easy2boot-usb-drive/ makes a USB drive that is 1. live bootable 2. presents boot options from whatever .iso files to copy to the FAT32 formated USB drive. 3. allows storage of files for persistant data when the live boot is running; just mount the partition:
  https://superuser.com/questions/311976/casper-rw-persistence-on-fat32-partition/862355#862355
   
• http://unetbootin.sourceforge.net/ for an excellent windows or linux utility that can very easily make bootable USB drives for a number of different operating systems, including UNIX / Linux, FreeDOS, and several utility systems.

OTHER OPERATING SYSTEMS are availible for the IBM PC. These include:

• Digital Research CP/M-86
• Digital Research Concurrent CP/M-86 (multitasking)
• Digital Research Concurrent DOS (PC-DOS compatible, multitasking)
• Digital Research Concurrent DOS XM (PC-DOS compatible, multitasking, multiuser)
• Digital Research Concurrent DOS 386 (same, for 80386 computers)
• Digital Research DR-DOS 3.31, 4.0, 5.0 & 6.0 (PC-DOS clones)
• http://www.freedos.org Free DOS for free people!
• http://www.datalight.com embedded DOS
• Wendin-DOS (PC-DOS compatible, multitasking, multiuser)
• XENIX
• QNX (multitasking, multiuser)
• PC-MOS/386 (PC-DOS clone, multiuser, multitasking)
• OSKD Simple 386 operating system kernel with drivers, D.Lindauer oskdl10.zip 546008 Jul 3 1995 (TASM source)
• geezer's x86 OS Development page
• V2_OS: The fastest (?) Operating System available for the 386+ PC ! Everything in this system is focused on speed: the architecture, the filesystem, it's avoidance of virtualization, everything. And of course, the choice of development language: The V2_OS is written in 100% pure 32Bit Assembler !
• OS/2

Operating systems are available for other (non-IBM) PC's

• 8080/Z80 based systems
  • Digital Research CP/M ( see the Altair 8800 simulator under Emulators / Computers )
• Apple
  • OS X

"Operating System: A seething mass of linked lists." - ~David Fellows

See also:

• http://www.bootdisk.com get recovery boot images for almost any OS.
• The most important part of a multitasking operating system is the task switcher. Some simplified task switchers have been developed for the PIC; see multitasking.htm .

THE OPERATING SYSTEM HIERARCHY

The Disk Operating System (DOS) and the ROM BIOS serve as an insulating layer between the application program and the machine, and as a source of services to the application program. The system heirarchy may be thought of as a tree, with the lowest level being the actual hardware. The INTEL\80x86 or NEC\Vx processor sees the computer's address space as a ladder two bytes wide and one million bytes long. Parts of this ladder are in ROM, parts in RAM, and parts are not assigned. There are also 256 ports that the processor can use to control devices. The hardware is normally addressed by the ROM BIOS, which will always know where everything is in its particular system. The chips may usually also be written to directly, by telling the processor to write to a specific address or port. This sometimes does not work as the chips may not always be at the same addresses or have the same functions from machine to machine.

Questions:

• sooraj_v at yahoo.com asks:

  ive got a data recovery software and i want to take it with me in a floppy.but the software requires registration everytime and when i register it gets registered to that only machine.so i planned of creating a ramdrive and placing it there.i did it and got the drive letter of that drive and could copy that software to ram.but unfortunately that software does not work when himem.sys is loaded (loaded himem for extended memory).so i found another ramdrive creator(vdisk.sys) which did not require himem.sys for creating a drive of 2mb.please tell me a way of how to access the drive letter or any other way for my ramdrive.

  I don't understand. None of the data recovery software I've seen ever require "registration". I think the most popular data recovery packages are Tom's root boot rescue floppy and the Knoppix Live CD .

Comments:

• see microchip/multitasking.htm

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