facebook.com/history. c-span's coverage of the solar eclipse starts at 7:00 a.m. eastern with the "washington journal" live in maryland. and aests are a scientist chief scientist. we join nasa tv at noon as they provide live use of the eclips'' s shadow passing over north america. at 4:00 p.m. eastern, the reaction to this rare solar eclipse across the continental united states. on monday at 7:00 a.m. eastern on c-span and c-span.org. listen live for free on the c-span radio app. this weekend, "american history tv is featuring highlights from the c-span

cities tour. mr. spicer: right now, we are in the revolution exhibit at the computer history museum in mountain view, california. behind me are over 1000 artifacts that tell about the history of computing, going back to thousand years. the exhibit is laid out into 19 galleries, each one focuses on a certain theme or object from the history of computing. for example one of those themes , is real-time control. here we look at things like pacemakers for hearts. these are computer systems that must function. they're not like your laptop, which can crash once in a while and the worst is that you lose your work. if a pacemaker crashes, you die. the oldest item is a set of what are called napier's bones, small ivory counting sticks from the 17th century. the most recent thing we have is an iphone, the first model.

we are in the punchcard gallery. behind me, you see a replica of an 1890 census machine. what is this? in the bureau of the census had 1890, just finished the census, which requires a census to be taken every 10 years. the 1890 census was not going to be completed in time. so someone came up with a method to do this mechanically. typically way this system works was, the census taker would go out in the field and asked the usual questions, bring them back to the office, where they would be transcribed using this device, called a pantograph, which converts the handwritten responses into machine-readable form. using this blank piece of cardboard at the top, the census clerk punches holes in the card, which correspond to the answers in the census. what he did by doing this is create the census results and move them from human readable

form to machine-readable form. once he did that, he could put the punch cards inside his census machine, which worked by counting each of the holes in the card. this was a real success story. the 1890 census was completed in about three years even though -- in three years, even though there were millions of new immigrants and quite a few more questions. why this is important is because a company called ibm ultimately grew out of the patents and dominated computing for most of the 20th century. his punch cards, also called ibm cards, were the main way that people interacted with computers for most of the 20th century. right now, we are in the memory and storage gallery. behind me is the world's first hard disk drive, invented in 1956 at ibm san jose by a team led by ray johnson, a retired schoolteacher who is good at inventing, no formal engineering training.

the great advantage of a hard disk was it could replace punch cards, so rather than having hundred thousand punch cards in a drawer, you could just have one of these discs. the difference, too, is that you have to sort through punchcards to find the information, compared to a disk drive, you can jump directly to the information you need, so it is much faster. this device is so well made that it still functions. we have a team ofvolunteers who -- we have a team of volunteers who demonstrate once a week. one of the first things they noticed is that there was 60-year-old data still on the hard disk. the disk drive has not changed . we are still using them today but have a read/write head and a motor that spins around. welcome to the minicomputer gallery these came out in the mid-1960's and were computers that small businesses can afford. beside me is one that was , advertised as the kitchen

computer in a neiman marcus catalog. it cost $10,600 and neiman marcus did not sell any. part of the problem is that the program in it, in this case the -- program it, the user, in this case the housewife, would have to know a numbering system and would have to be able to read in this code and also programmed the computer using these switches in that code, almost an impossible task for most people. generally, you would attach a kind of keyboard to this to make it work. we have it here in this gallery to show that even though it was not practical, it shows the beginning of people thinking about putting computers in the home. we are sitting in front of a xerox alto, which came out in 1972 and was revolutionary. it had a system that used a desktop metaphor of pulldown -- metaphor with pulldown menus, it had ethernet, laserjet printing, email, and spreadsheets and word processing in 1972.

steve jobs saw this machine and was inspired to create the lisa at apple, which became the macintosh. the things that we take for granted, the desktop metaphor, garbage can, pulldown menus, icons on the mac and windows, all came from the xerox alto. there is a funny story in the history of computing where steve jobs allegedly complained to bill gates that bill gates had stolen the idea for windows from apple. bill gates responded, that is not true, we both stole it from xerox. that shows you the intellectual debt that the alto generated and which continues to affect us today and the computers we use. we are in the personal computer gallery right now, which shows the different microprocessor-based computers that were for sale in the 1970's and 1980's. we still use them today, but that was the heyday. the most significant one is right here, the apple one

computer designed by steve wozniak and steve jobs. they sold about 120 of these, many assembled, some you could build in kit form. that is woz's signature on the top. the apple one was a hobbyist machine so it was aimed at gear heads, people who like soldering and connecting things to their tv. on the basis of this, steve jobs said, "if we made a computer for normal people rather than nerds -- no offense -- i think we could sell a lot more." the computer that resulted was called the apple ii. apple was created by the two steves, wozniak and jobs, and the machine that put them on the map was the apple ii, 1977, 48

kilobytes of memory -- not megabytes or gigabytes -- and provided color, unusual for the time. very few personal computers offered color. on the basis of the apple ii, apple kept itself afloat for many years. the first few years of sales of the lisa and mac were very disappointed and it was only because of the strong apple ii sales that apple was able to say in business. in total, the apple ii remained an apple product for an astounding 17 years. a few years later, ibm joined the party. apple took out a full-page ad in the wall street journal and said, "welcome ibm" -- seriously. the ibm pc was not the most advanced computer, but it had the very important job of legitimizing personal computers for business. until this time, most businessmen looked at these microprocessor-based computers like the apple and the commodore as basically toys, suitable for home or education, but not business. it took ibm's entry into the field in 1981 with the pc to finally put a stamp of approval

and legitimacy on the pc. you could actually do business tasks using an ibm pc. ibm's initial strategy, being a purveyor of mainframe systems, was to protect the mainframe at all costs. that was generating their billions of dollars in profit. a mainframe computer is literally a room sized computer filled with spinning tape drives and hard drives and people running around. the ibm pc was initially viewed as something that would connect to the mainframes and only later was something to stand alone and used by an individual. we are now in the networking and web gallery. beside me, we have google's first web server. at the time, google was a very small company with limited funds. what they did was build their equipment cheap. they went to a local electronics store and bought a whole bunch of ibm pc-compatible circuit boards and mounted them to this large cabinet.

the cabinet acted like a search engine. if you did a google search in 1999 or 2000, there is a good chance your search went through this very machine. this system is actually made out of cork board. if you look underneath all of these pccircuit boards, they are actually separated by a very thin layer of cork, like the cork in a wine bottle. that layer of cork is the only thing keeping the whole system from bursting into flames, so it is actually remarkably poorly designed in a sense. it is not safe really. nonetheless, for starting a business when you are running out of your garage or a small business, this was perfect for them. one of the things we tell, especially schoolkids when they come, is that a computer is a tool like a hammer. with a hammer you can brain someone over the head or build a house. in one case, it is evil and in the other, it is great.

it does something useful. it is the same with computers. we are seeing the human or social impact of how everyone having a computer in their pocket is affecting how we live. there are lots of negative consequences -- insomnia, people feeling lonely in spite of being surrounded by cyber friends, the sort of spurious friendship that occurs on facebook -- you call them friends but they are really not friends -- and the pace of life now i think is the single greatest risk to human sanity in the next 20 years or so. the desire, which we impose on ourselves seemingly, the always -- to always be on, always be responding to text or emails are -- or looking up websites. we don't just sit down and watch the sky anymore. >> you can watch this and other

programs on the history of communities across the country tour.pan.org/cities this is american history tv only on c-span3. this year marks the 325th anniversary of the salem witch trials. tv, on american history kenneth foote talks about memorializing sites like salem. his book on the subject is called "shadowed ground." this hour-long speech is from the salem state university symposium on the legacy of the witch trials. >> my name is shelby. this is our 25th anniversary as we were formed on the centenary