# how efficient were punch cards in today's terms? **URL:** \ **Category:** Factual Questions\ **Created:** [May 1, 2009, 9:12am UTC](https://boards.straightdope.com/t/how-efficient-were-punch-cards-in-todays-terms/494952 "2009-05-01T09:12:29Z")\ **Posts on this page:** 6\ **Page:** 4
**Author:** ![FORTRAN\_forever](https://avatars.discourse-cdn.com/v4/letter/f/f17d59/32.png) [@FORTRAN\_forever](https://boards.straightdope.com/u/FORTRAN_forever)\ **Post date:** [May 3, 2009, 2:59pm UTC](https://boards.straightdope.com/t/how-efficient-were-punch-cards-in-todays-terms/494952/61 "2009-05-03T14:59:40Z")
> [@FORTRAN\_forever](#): > > Back in the sixties IBM mainframe computers used “core memory”. My apologies for not including the obligitory [wikipedia reference](http://en.wikipedia.org/wiki/Magnetic_core_memory)in the above message. It’s much better than my simple description, and includes pictures of actual cores along with specific descriptions of how they worked. For one thing, reading memory was actually a lot more complicated (and took a lot longer) than writing memory did, as “reading” memory actually involved writing to it, then sensing whether or not that write resulted in the bit changing state, then (if the bit had changed state), writing the original value back onto it (AKA a “destructive read”). It’s a bit like detecting whether your car window is up or down by throwing a brick through it, then replacing the window if it had shattered. ---
**Author:** ![ZenBeam](https://avatars.discourse-cdn.com/v4/letter/z/3ab097/32.png) [@ZenBeam](https://boards.straightdope.com/u/ZenBeam)\ **Post date:** [May 3, 2009, 4:32pm UTC](https://boards.straightdope.com/t/how-efficient-were-punch-cards-in-todays-terms/494952/62 "2009-05-03T16:32:52Z")
> [@FORTRAN\_forever](#): > > OK, if you’re looking for a size comparison in terms of storage media… > > Back in the sixties IBM mainframe computers used “core memory”. They were little donut-shaped things, each just big enough to see individually. They were strung together in a grid pattern using tiny wires. As I recall, 256K of memory filled a storage cabinet (think of a small telephone booth), so a megabyte of memory required four cabinets. I don’t know how much each cabinet cost, but I’m confident that is was expensive. > > So your typical $40 16GB USB memory stick would have required about 64,000 telephone-booth sized boxes of memory back in the sixties. Now **Bamboo Boy** just has to explain to his stepson what a telephone booth is… ---
**Author:** ![yabob](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/yabob/32/2821_2.png) [@yabob](https://boards.straightdope.com/u/yabob)\ **Post date:** [May 3, 2009, 5:08pm UTC](https://boards.straightdope.com/t/how-efficient-were-punch-cards-in-todays-terms/494952/63 "2009-05-03T17:08:01Z")
> [@Voyager](#): > > I think the measurement is in the information theory sense, how much of the theoretical bandwidth got used. In this sense they were less efficient than paper tape, but in the sense of reducing the amount of rework they were a lot more efficient, since you didn’t have to punch an entire new card deck for a simple change. Paper tape was also SLOW, and prone to errors. One memory I have from school: The CS department had a number of projects going involving use of Tektronix scopes and topographic map data. To get the data, they had to digitize a lot of topo maps, and paid students to click around all the contours on a large digitizer table belonging to Civil Eng. The rub was that said digitizer table was in a little room in the CE department, hooked up to a tiny little stand-alone computer which had a model 33 teletype connected to it. One of those TTL era things that had built-in BASIC, and could handle maybe a few hundred lines of code. The ONLY way to get data out of the thing was to spit it out to the paper tape on the teletype. And CE was totally adamant that THEIR digitizer was NOT going to be connected to anything not belonging to them. Consequently, the CS department’s project involved messing with shelf after shelf full of reels of paper tape containing topo map data. Lord knows how many hours were spent shlepping those paper tape reels around, transferring the data to the campus mainframe, and massaging it to fix all the errors, probably a combination of data entry errors, and errors arising from the paper tape medium itself. ---
**Author:** ![Bamboo\_Boy](https://avatars.discourse-cdn.com/v4/letter/b/839c29/32.png) [@Bamboo\_Boy](https://boards.straightdope.com/u/Bamboo_Boy)\ **Post date:** [May 4, 2009, 12:09pm UTC](https://boards.straightdope.com/t/how-efficient-were-punch-cards-in-todays-terms/494952/64 "2009-05-04T12:09:10Z")
> [@FORTRAN\_forever](#): > > OK, if you’re looking for a size comparison in terms of storage media… > > Back in the sixties IBM mainframe computers used “core memory”. They were little donut-shaped things, each just big enough to see individually. They were strung together in a grid pattern using tiny wires. As I recall, 256K of memory filled a storage cabinet (think of a small telephone booth), so a megabyte of memory required four cabinets. I don’t know how much each cabinet cost, but I’m confident that is was expensive. > > So your typical $40 16GB USB memory stick would have required about 64,000 telephone-booth sized boxes of memory back in the sixties. Cool! THAT’S the kind of mind-blowing comparison I was thinking of. > [@ZenBeam](#): > > Now **Bamboo Boy** just has to explain to his stepson what a telephone booth is… Hahahahaha. They are exceedingly rare here in Copenhagen… ---
**Author:** ![ftg](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ftg/32/2801_2.png) [@ftg](https://boards.straightdope.com/u/ftg)\ **Post date:** [May 4, 2009, 4:41pm UTC](https://boards.straightdope.com/t/how-efficient-were-punch-cards-in-todays-terms/494952/65 "2009-05-04T16:41:33Z")
I don’t recall the exact amount but 16K of core memory for an IBM 1130 was cited as costing $200-400K in the early 1970s. Ours had 3.3 microsecond memory read cycle (and a 1Mbyte disk). Back in the days when “core” meant “core”. My rule of thumb is that most everything is something like 500-5000 times “better” now than then. (Speed, capacity, etc.) ---
**Author:** ![SCSimmons](https://avatars.discourse-cdn.com/v4/letter/s/e495f1/32.png) [@SCSimmons](https://boards.straightdope.com/u/SCSimmons)\ **Post date:** [May 4, 2009, 5:28pm UTC](https://boards.straightdope.com/t/how-efficient-were-punch-cards-in-todays-terms/494952/66 "2009-05-04T17:28:05Z")
> [@scr4](#): > > And if that file were a 64kbp MP3 file, to play back the file you’d have to read the cards at a rate of about 100 cards per second. Would that have been feasible? [Playing MP3’s is boring.](http://ars.userfriendly.org/cartoons/?id=20011229) 😃 [Previous page](https://boards.straightdope.com/t/how-efficient-were-punch-cards-in-todays-terms/494952.md?page=3)