Learning Computing History

A Brief History of Operating Systems

OS – A program that controls the execution of application programs and acts as an interface between the user and the hardware.  It does a high degree of coordination of resources in terms of memory, CPU cycles or process, I/O devices and file system.  

Back in the early days, program execution required significant preparation, physical separation of users and equipment led to the OS, which is a system to simplify program setup and simplify transition between jobs.  

An OS function:

• Communicate or provides a method for other programs to communicate with the hardware.
• Create a user interface—a visual representation of the computer on the monitor, and also enable user to manipulate the interface or changes to the computer.
• Enable users to determine the available installed programs and run, use, and shut down the program at their choice.
• Enable users to add, move and delete the installed programs and data.
• The internal part of the OS is called the Kernel comprised of:
  • File Manager
  • Memory Manager
  • Device Drivers
  • Scheduler
  • Dispatcher

The Evolution of the OS

The Ancestors (   - 1945)

•  Hardware mechanical
•  No OS at all, built for a specific purpose
• Code change by moving cables (!)
•  Terminal are blinking lights; punch cards
•  No interaction

Ø       Z3, the 1st programmable computing device, developed by Konrad Zuse, German engineer in 1941,

Ø       Colossus (UK), a device to decode German ENIGMA transmissions was built by the British & developed by Thomas Flowers, Max Newman & Associates of Bletchley Park in 1943

 

Pre-OS Stage

No real OS to speak of; hardware costs outweighed human cost (1945-1955)

• Singular job processing & card fed libraries; hard-wired structure where changes & debugging are complicated.
• Demand for alternative uses of computing equipment led to the ability of reprogramming via switches & modular sections instead of soldered connections

Ø       ENIAC, the world's first electronic digital computer, was designed by John Mauchly and J. Presper Eckert for Army Ordnance to compute World War II ballistic firing tables in 1947.

Ø       EDSAC (or Manchester Mark I) (UK), was a follow on employing many of John Von Neumann’s principles.  Lead by John E. Lennard-Jones &  Maurice Vincent Wilkes in 1948

Ø       UNIVAC/LARC, the first “so–called” supercomputer, was developed Herman Lukoff, founding member of Sperry-Rand, 1951

OS Stage 1

• Simple OS structure – simple batch processing (1955 - 1965)
  • No memory management & protection
  • Punched Card  & tape program input
  • Monitor console to oversee job processing
  • Job debugging still complicated requiring dumps to debug
  • OS develops sophistication – overlapped CPU & I/O operations (1962 - 1969)
    • Buffering of slow jobs to fast tape & replicate I/O devices
    • Ability to Spool jobs to disk

Ø       MULTICS, a mainframe timesharing operating system, announced in 1963, not released until 1969

Ø       IBM OS/36, state-of-the-art, was released with over 1000 known bugs in 1964

OS Stage 2

• OS extends to multi-programmed batch systems (1965 - 1970)
  • Multiple jobs on disk waiting to run
  • Multiprogramming – run several programs at the same time
    • Load jobs into memory as Schedules Jobs
    •  Load jobs that await tapes to be mounted
• Interactive timesharing (1970 - 1980)
  •  One computer, many low-cost terminals
    • Concurrent user access of resources
    • Simpler debugging
  • Disk space becomes cheaper so programs are loaded to disk subsystems

Ø       UNIX, developed by Ken Thompson at Bell Labs, became a successful OS on the UNIVAC in 1969

Ø       First microchips appeared from both Intel & Fairchild independently of each other in 1970

Ø       DEC VAX11 780, Enhanced PDP-11 architecture to increase virtual address space from 16 to 32 bits, doubling general registers from 8 to 16 in 1978

OS Stage 3

• Personal Computing (1980 - 1995)
  • One CPU per computer instead of dumb terminals (Computers for the masses!)
  • OS at the desktop is simplified by removing support for concurrency, memory protection & multiprogramming
  •  Emphasis on user interface & API

Ø       In 1977, Kildall & Digital Research re-wrote CP/M to make it suitable for running on the many microcomputers using the 8080, Zilog Z80, and other CPU chips.  

Ø       IBM 5150, the original “Personal Computer” which defined the term PC-Compatible in 1981

Ø       IBM accepted Gates’ DOS/BASIC package.  The revised system was renamed MS-DOS and quickly came to dominate the IBM PC market. 

Ø       Apple Lisa, ahead of its time, featured a mouse, icons, pull down menus, point and click, cut’n’paste in 1983, Apple Macintosh was the first affordable computer to include a Graphical User Interface in 1984. Apple products were developed under Steve Jobs & Steve Wozniak

Ø       Windows 3.1 over MS/PC/DR-DOS OSes allowed the PCs to utilize a GUI for the 1st time in 1985.

Ø       The desire for a free production (as opposed to educational) version of MINIX led a Finnish student, Linus Torvalds, to write Linux in 1991.

OS Today

• Cutting Edge Computing (1995 - 2003)
  • High performance computers with pre-emptive multi-threaded multitasking OS layered with an intuitive GUI
  • Turnkey desktops & portables with applications & services ready for use OOB
  • Networked-assembled systems
  • End user skills minimalized to appliance implementer

Ø       Windows 9x (1995), although not purely 32-bit, it offered a family of stable personal desktop OS

Ø       Windows NT 4 (1996), Windows 2000 (2000), Windows XP (2001), From the ground up, the OS has been based on a secure model for the business environment, finally merging with the personal desktop in XP

Ø       MAC OS X PPC (2001), adopting a UNIX core, this GUI is powered by the PowerPC CPU.

OS Diversity: Each OS iteration is spawned by the advances achieved in their predecessors.  Each advancement in CPU development leads to more sophistication in the OS as well. 

From the onset of computing, the OS has manifested itself from Single-User Systems, thru Batch processing, Spooling, Time Sharing, Multi-processing, Distributed Computing, Real-Time Computing,, Parallel Computing and beyond to the limit of our imagination.