Many years ago, I used to maintain a PDP-8/I. It was used to enter telegrams. There were several terminals where the operators worked. The PDP-8 sent the telegrams to another computer, a Collins 8500, which sent them across the country and around the world.
Back in the late 60s and 70s I worked in a semiconductor manufacturing plant where many machines like this were used to control parts sorters, device testers and data collectors etc. My job was repair and maintenance, but I had many opportunities to write programs that made my job faster and easier. These machines were a lot of fun to play with, my compatriots and I regarded computers like this to be the ultimate toy.
When I first started college, we had some of these machines. I recall a game that we had where it would take 3-letter words and it would randomize them - you had to type in the actual word, and one could get very quick at it. I suggested that to make the game harder that we replace the vocabulary in the game with PDP-8 assembly mnemonics - others thought that this would make the game far to hard, so I never actually did this.
Removed 2 of these from a London Hotel in 1980. It had 10 years on the timer. Consisted of a paper tape reader and a 500K byte fixed disk hard drive. Also an intercommunication system so it could work in tandem with a second system which it used for redundancy. Have pictures if anyone interested.
In the 70s my high school had a PDP 8e with a Teletype terminal with a paper tape reader. To start her up we had to manually enter an assembly language program into memory via the toggle switches. That program merely taught the machine how to communicate with the Teletype. At that point we could then load the OS using the paper tape. The language was FOCAL, I believe.
I never touched one of these, but this reminds me of the computer I did work on while serving in the Navy. It was a Univac 1219, otherwise known as the Mk 152 computer, and was the brains behind the Terrier missile system in those days. Looked just like this but was the size of a refrigerator. Look it up sometime and be amazed at just how far technology has come since those days.
One thing I recall from the PDP-8 programmers reference was they actually recommended self modifying code, which is normally considered a big NO NO! This was to get around the very limited instruction set.
This brings back a lot of memories. I used a PDP-8 in the early 80s, but it was a PDP-8A with a keypad instead of toggle switches. Same instruction set, though.
Very nice video - I used 2 of these linked together in the early 70's. The 8i was had those really nice switches (vs the 8e)....I think someone reversed the "deposit" key on ours, because I remember entering values and the just swiping across the top (hitting the reversed deposit key, and then clearing the switches all in one swipe). I moved a few years ago and finally through out my cooper colored "Introduction to Programming" book.... which I had kept it and given to someone like you !!
Putting main programs or data at addresses 10-17 is pretty much a no-no because those are the auto-increment addresses. References to those addresses by "indirect" addressing has the contents incremented first, so they were reserved for that specific need. Address 0 is reserved because that's where Interrupt routines start. Indeed, all of page 0 is reserved since it can be accessed from anywhere else in each 4k field. Typically, programs started at 0200 octal, which is the first address outside of page 0.
Nice Demo - The PDP-8 was the first computer that I worked with in University back in 1972. I just finished building a PiDP-8 kit I will try this program as soon as I place everything into the case.
Thanks for a trip down (ahem) Memory Lane. My access to the front panel was limited, due to my lowly status and that the system ran a time-sharing system with many active users at the College and surrounding High Schools. All user interface devices were ASR-33, except for a local CRT terminal. Off-site access was dial-up at 300 baud on "conditioned" data lines. As far as I could determine, conditioning consisted of "red protected" covers on the bridging clips and terminal posts and a string tag.
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In the mid 70s, I ran an entire city newspaper 60K circulation on a PDP-8e. We did
Many years ago, I used to maintain a PDP-8/I. It was used to enter telegrams. There were several terminals where the operators worked. The PDP-8 sent the telegrams to another computer, a Collins 8500, which sent them across the country and around the world.
Back in the late 60s and 70s I worked in a semiconductor manufacturing plant where many machines like this were used to control parts sorters, device testers and data collectors etc. My job was repair and maintenance, but I had many opportunities to write programs that made my job faster and easier. These machines were a lot of fun to play with, my compatriots and I regarded computers like this to be the ultimate toy.
When I first started college, we had some of these machines. I recall a game that we had where it would take 3-letter words and it would randomize them - you had to type in the actual word, and one could get very quick at it. I suggested that to make the game harder that we replace the vocabulary in the game with PDP-8 assembly mnemonics - others thought that this would make the game far to hard, so I never actually did this.
Removed 2 of these from a London Hotel in 1980. It had 10 years on the timer. Consisted of a paper tape reader and a 500K byte fixed disk hard drive. Also an intercommunication system so it could work in tandem with a second system which it used for redundancy. Have pictures if anyone interested.
In the 70s my high school had a PDP 8e with a Teletype terminal with a paper tape reader. To start her up we had to manually enter an assembly language program into memory via the toggle switches. That program merely taught the machine how to communicate with the Teletype. At that point we could then load the OS using the paper tape. The language was FOCAL, I believe.
This must be what it's like to pilot the original Enterprise.
I never touched one of these, but this reminds me of the computer I did work on while serving in the Navy. It was a Univac 1219, otherwise known as the Mk 152 computer, and was the brains behind the Terrier missile system in those days. Looked just like this but was the size of a refrigerator. Look it up sometime and be amazed at just how far technology has come since those days.
A machine like this was my main focus in college in 1979.
One thing I recall from the PDP-8 programmers reference was they actually recommended self modifying code, which is normally considered a big NO NO! This was to get around the very limited instruction set.
This brings back a lot of memories. I used a PDP-8 in the early 80s, but it was a PDP-8A with a keypad instead of toggle switches. Same instruction set, though.
Very nice video - I used 2 of these linked together in the early 70's. The 8i was had those really nice switches (vs the 8e)....I think someone reversed the "deposit" key on ours, because I remember entering values and the just swiping across the top (hitting the reversed deposit key, and then clearing the switches all in one swipe). I moved a few years ago and finally through out my cooper colored "Introduction to Programming" book.... which I had kept it and given to someone like you !!
I've just made one of these. Great video. Learned a lot, Thanks
Putting main programs or data at addresses 10-17 is pretty much a no-no because those are the auto-increment addresses. References to those addresses by "indirect" addressing has the contents incremented first, so they were reserved for that specific need. Address 0 is reserved because that's where Interrupt routines start. Indeed, all of page 0 is reserved since it can be accessed from anywhere else in each 4k field. Typically, programs started at 0200 octal, which is the first address outside of page 0.
Thanks for sharing these steps. Great video.
Nice Demo - The PDP-8 was the first computer that I worked with in University back in 1972. I just finished building a PiDP-8 kit I will try this program as soon as I place everything into the case.
Thanks for a trip down (ahem) Memory Lane. My access to the front panel was limited, due to my lowly status and that the system ran a time-sharing system with many active users at the College and surrounding High Schools. All user interface devices were ASR-33, except for a local CRT terminal. Off-site access was dial-up at 300 baud on "conditioned" data lines. As far as I could determine, conditioning consisted of "red protected" covers on the bridging clips and terminal posts and a string tag.
Just built Oscar's PiDP-8, this video was a super helpful intro, thanks!
Nice tutorial. It's clear and easy to understand. Thanks.
Ideal for teaching machine codes and basics of how CPU works