The Many Levels of Abstraction in Computing Systems

The evolution of computing systems -- the world of bits -- is following a path similar to that of life, and now the two are merging!

The evolution of computing is vastly more rapid and better known than the evolution of life. Modern digital computing began early in WWII to facilitate tasks such as code breaking that required previously impractical volumes of tedious and error-prone arithmetic computations. These first computers executed the necessary sequence of logic and arithmetic operations as directed by hard-wired plug-boards, so the "programs" were hardware too.  Digitally programmable "stored program" computers first appeared in 1949. Programs-as-data stored in addressable memory allowed software and hardware to evolve somewhat independently. Thus the art of programming was born. The central abstraction of storing program instructions as data not only changed hardware architectures, it also introduced the notion that bits can encode something other than numbers.

The circuits underlying hardware representations of bits evolved from relays to vacuum tubes to transistors to integrated circuits and in some cases to optical circuits.  This progression created ever smaller and denser circuitry that increased both speed and storage capacity by orders of magnitude.  Today even smart phones contain multi-core CPUs. Large organizations coordinate tens or even hundreds of thousands of processors in massive server farms. Programs such as those that implement Google's page rank algorithms may run in parallel on hundreds of thousands of CPUs.  "Permanent" storage evolved similarly.  In 1980 a large mainframe might have had a few Gigabytes of spinning disk online. Now a teenager may have ten times that in his jeans pocket.   Human interaction with computers advanced dramatically as well. It began with plugboards and panel switches, then used teletypes and video monitors, and has since progressed through mice, touch screens (with "retinal" resolution) and now to voice-commands and gestures visible to the computer's camera or accelerometers.

Programming has evolved rapidly too. The "meaning" of the bits in stored programs co-evolved with new hardware features such as processor interrupts, pointers, register sets, floating-point processors, segmented memory and eventually virtual memory. To manage the increasing richness of hardware capabilities, programmers created code abstractions easier to understand than binary machine language: first assembly languages and then compiled or interpreted languages.  Compiled COBOL appeared in 1959, followed in 1960 by FORTRAN and soon thereafter LISP and ALGOL  In the early 1970's, C  and object-oriented languages, such as Smalltalk and Scheme emerged. Programming languages continue to evolve today because of the new demands created by the interpenetration of computers, society, and the Internet.

A more dramatic and important evolution occurred in what the data bits represented.  Initially bits represented binary numbers.  By the 1960's it became common to also use groups of bits to encode characters that could be entered and printed via teletype machines. By 1963 both ASCII and EBCDIC codes were standardized and FORTRAN, COBOL, and LISP were able to deal with character and string data types in addition to numbers. Text processing became practical. As Unix machines and PCs became commonplace, character string data overtook numeric data as the most common domain of computing. Now, character data is likewise outweighed by image, audio and video data.  And an increasingly wide array of sensors and actuators for all sorts of physical properties -- pressure, temperature, acceleration (in our iPods and iPhones), chemical sensors, radio, GPS signals, etc -- generate and consume data.   Now mobile devices can know where they are in the physical world and soon will be able to recognize by voice and face recognition the people nearby.

Computers not only interact with people and other computers, increasingly they interact directly with the physical world. They control real-world processes such as traffic lights, car engines, chemical plants and nuclear power plants.  They fly planes and drive cars. They control various robots (now fairly primitive, but...). And computer controlled 3-D printers turn digital models of objects into actual objects.

The Web, has spawned all sorts of emergent multicellular computing constructs such as infectious viruses and worms, search engines, multi-player Internet games, peer-to-peer networks, wikis, blogs, social networking sites, folksonomies, photo sharing, Skype, Web Services, mashups, and Web 2.0. We also witnessed the growth of Cyber crime and now Cyber warfare, e.g., via Stuxnet and Flame.

In the stratosphere of Cyberspace we find "The Cloud." Of course, the Cloud is merely a marketing metaphor. Nonetheless, it is a metaphor that provides real Internet connected services specialized for attracting mobile devices and their cyborg human partners.  So the Cloud "serves" hundreds of millions of cyborgs.  And therein lies a lucrative space to be exploited by the most adroit services.  Each "Service" tends to be nominally free, but it is "monetized" by selling the information about the cyborgs, their friends and other relations (real as well as are virtual) gathered in the process of providing the service.  The very real and masive warehouses of "Big Data" computers that provide such services also watch over analyze and permanently remember virtually all interactions in this "Cloud". The Cloud knows all, sees all, and remembers all.  Only angels are truly safe in The Cloud.

We've come a long way, baby!

What is amazing is that the evolution of the “virtual” world occurred so rapidly. Modern high-tech human societies are the result of more than 13 billion years of step by step evolution from the first atoms.  Yet a mere 70 years after the first true digital computer, humans are beginning to be influenced as much by bits as by atoms. The evolution of life and the evolution of computing are merging, bringing the complexity of both realms together in completely unforeseeable ways.

Contact: sburbeck at
Last revised 7/21/2013