Grace Hopper: Computer Scientist

Grace Hopper: Computer Scientist — page 3 — computer company had asked Hopper to write coding instructions to run programs on its Binary Automatic Computer BINAC which was being developed for Northrop Aircraft Corporation’s secret Snark Missile project BINAC was able to perform high-speed arithmetic and was the world’s first computer that contained stored programs It contained approximately 700 vacuum tubes and was too large to easily move once it was set up Each workday the 42-year-old Hopper lived in a world of octal converting base-ten numbers into The First Computer English mathematician Charles Babbage is credited with being among the first people to talk about building a calculating machine In the early 1820s Babbage was frustrated with the unreliability of printed tables used for calculations Such tables commonly were used for everything from navigation to banking to construction Yet the tables were not perfect They contained errors caused by miscopying or miscalculations Babbage dreamed of a way to automate creation of these tables which would remove such errors He believed machines unlike humans would not make mistakes in their calculations In 1822 he drew up designs for a difference engine that would add numbers However because he lacked funding and a skilled machinist who could craft it to his specifications he was not able to build it Babbage had assistance in his work from young mentee Ada Lovelace In writing about Babbage’s designs Lovelace described how codes could be created so the machine could handle letters and symbols as well as numbers She also came up with the theory of looping which is when a computer repeats a series of instructions For these and other contributions Lovelace is often referred to as the first computer programmer 6

Grace Hopper: Computer Scientist — page 4 — their base-eight equivalents so she could enter them into the computer At that time octal was considered to be the most efficient way to accomplish the task Yet outside of the office Hopper needed to use the conventional base-ten system Hopper realized she had two choices Either she could become better at the language the computer was using or the computer could become better at the language she was using She decided it would be more efficient to teach the computer how to process language that was more familiar to people Hopper would soon shift focus to work on another computer using a different programming language But the core desire to make computers communicate with people more easily stuck with her PROGRAMMING THE UNIVAC In mid-1949 Hopper moved from working on the BINAC to a different project at EMCC called UNIVAC for Universal Automatic Computer In the eyes of EMCC founders and former professors John Mauchly and J Presper Eckert UNIVAC was going to revolutionize computers They envisioned a high-speed electronic digital computer with an ability to work with problems that involved both numbers and words Early computers could only work with numbers which limited their abilities If they could be redesigned to compute words as well computers would become an exciting new tool for businesses 7

Grace Hopper: Computer Scientist — page 5 — Octal vs Decimal Octal is a number system consisting of eight single-digit numbers zero one two three four five six and seven It is a base-eight system in contrast to the base-ten system that people use commonly When she worked with BINAC Hopper had to convert decimal numbers into octal equivalents BINAC would then convert the octal numbers into binary code which consists of two numbers zero and one The zeros and ones worked like on and off switches with one being on and zero being off Binary code could run faster than coding of normal numbers Even today’s computers store information and operate in binary Yet in 1949 data was still being entered largely by people tapping numbers on keypads Entering information in binary takes a lot of time and numbers Octal helped reduce the size of those numbers For example the number ten in binary must be entered as 1010 In octal it must be entered as 12 That change saved time and reduced the potential for mistakes to use as well as for scientific purposes He Mauchly was envisioning much larger problems which hadn’t even been stated yet Hopper recalled He was visualizing the use of computers in the business and industrial area the things that they would be able to do 1 Hopper had become head of the software division at EMCC and she was assigned to program UNIVAC A programmer provided the computer with a list of instructions to carry out This was done using a punch card which was a stiff piece of paper with holes punched in specific patterns that represented data These were inserted into the computer which read the holes in the cards and translated them into information Hopper hired a team of four men and four women to assist her in building a collection of 8

Grace Hopper: Computer Scientist — page 6 — SCIENCE SPOTLIGHT PUNCH CARDS Modern computers allow users to save files which can be opened and changed at any time However when Hopper was beginning to work with computers data was accessed by inserting a punch card into the computer Punch cards were created by inserting a thick paper card into a punch card machine Holes were then punched in columns to represent characters Once the punch card was completed the desired data was stored on the card One drawback of the punch card was that it held a limited number of holes and therefore limited data If a large amount of data needed to be stored multiple cards were necessary It was crucial that the cards remained in a stack in the correct order so that the machine could read the data in the correct order When the user loaded the program each card was inserted into a punch card reader that input the data from the cards into the computer Punch cards date back to the early 1700s Textile looms could be controlled by punch cards The loom followed a sequence of operations based on white punch cards with holes and wove patterns based on the data the cards provided In 1725 a French weaver named Joseph-Marie Jacquard used punch cards to create a self-portrait woven in silk 9

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