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1956 IBM hard drive
"Short Wave Sportfishing" wrote in message ... On Tue, 4 Dec 2007 08:29:22 -0500, "Eisboch" wrote: http://www.neatorama.com/images/2006...puter-1956.jpg In September 1956 IBM launched the 305 RAMAC, the first computer with a hard disk drive(HDD). The HDD weighed over a ton and stored 5MB of data. That's not a typo ..... 5MB of data. If I remember correctly, the ones that DEC and DG built used head motors that weighed 160 pounds and were made out of cast aluminum. Damned things were bigger than washing macines. Motors were not that heavy. But the voice coil magnets were about 15 pounds. Still have a couple of them stuck to the side of the tool chest. |
1956 IBM hard drive
"Eisboch" wrote in message ... wrote in message ... On Tue, 4 Dec 2007 17:09:22 -0500, "D.Duck" wrote: The IBM 350 disk system stored 5 million 8-bit (7-bits plus 1 odd parity bit) characters (about 4.4 MB). http://en.wikipedia.org/wiki/IBM_305 Somebody needs to fix the Wiki. It was 7 bits (remember the "odd parity"?) The bits are 1, 2, 4, 6, A, B and parity. It goes with "7 track tape" etc. The most popular military teletype machines (Mod 28 ASR33) were 7 bit ASCI with an 8th parity or "stop" bit. Eisboch Eisboch Model 28 is 5 bit and Model 33 is 8 bit. In the 8 bit ASCII code the 8th bit is the parity bit. The stop bit is usually two bits in length and was in incorporated to help "synchronize" the sending and receiving terminals. |
1956 IBM hard drive
On Dec 4, 9:23 pm, Short Wave Sportfishing wrote:
On Tue, 04 Dec 2007 20:22:06 -0500, Wayne.B wrote: On Tue, 04 Dec 2007 23:13:55 GMT, Short Wave Sportfishing wrote: My first computer had a paper tape reader and I had to cold start boot strap it. The first computer I ever programmed was like that: Summer of 1967, Control Data 160A, 4K 12 bit words, as big as a large desk, cost approx $80K, paper tape in, paper tape out, environmental requirements: 72 degrees F +/- 2 degrees, 50% humidity +/- 10%. We copied the cold boot tape onto metalic mylar to keep it from wearing out quite as fast. Bear in mind that $80K then was like $500K now. Surprisingly enough we actually got some useful work out of the machine and I launched my entire adult career with it. Technically, I suppose my first "personal" compuer was an original Roberts calculator kit. One of the AF Captains in the survival course at Kessler knew him and we got to talking and he obtained one for me. Pretty cool deal. Next up was an Altair 8800 when I went to work for DG - basically the front panel was a duplicate of the original Nova computer. I know I've told the story about programming the computer at Sylvania with phone jacks.- Hide quoted text - - Show quoted text - I remember my brother was going to school and bought a calculator for his electronics and math courses. It was a TI and he payed something like $150 for it. I thought it was amazing because it would do square roots! Of course, it took him a long time to trust it, he'd check it with his slide rule. I learned to use his slide rule while I was in high school, never forgot, although by the time I got to college, calculators had come a long way, although I will never forget the day I got my first HP 48G. |
1956 IBM hard drive
wrote in message ... On Tue, 4 Dec 2007 23:27:19 -0500, "Eisboch" wrote: wrote in message . .. On Tue, 4 Dec 2007 17:09:22 -0500, "D.Duck" wrote: The IBM 350 disk system stored 5 million 8-bit (7-bits plus 1 odd parity bit) characters (about 4.4 MB). http://en.wikipedia.org/wiki/IBM_305 Somebody needs to fix the Wiki. It was 7 bits (remember the "odd parity"?) The bits are 1, 2, 4, 6, A, B and parity. It goes with "7 track tape" etc. The most popular military teletype machines (Mod 28 ASR33) were 7 bit ASCI with an 8th parity or "stop" bit. Eisboch Eisboch This wasn't ASCII, it was Binary Coded Decimal. The problem with even parity is a "blank" is even. All IBM machines used some varient of BCD before the 360 and "hex" That was a typo above bits are 1, 2, 4, 8, A, B parity. Maybe you're right ... it's been a long time. I seem to remember though being taught that the military teletype machines that I worked on were 100 wpm (or maybe it was 110 wpm), 8 bit ASCII. Several machines would be running in the radio shack copying several channels of an multiplexed fleet broadcast. I used to have a manual that I "borrowed" but I haven't seen it in years. I *do* have a little card that the Navy awarded you when you graduated from the school in Norfolk. It has your name, date, and confers the title of "Doctor of Teletype Technology". :-) I am probably wrong, but that's what I remember. Eisboch |
1956 IBM hard drive
wrote in message ... On Tue, 4 Dec 2007 23:27:19 -0500, "Eisboch" wrote: wrote in message . .. On Tue, 4 Dec 2007 17:09:22 -0500, "D.Duck" wrote: The IBM 350 disk system stored 5 million 8-bit (7-bits plus 1 odd parity bit) characters (about 4.4 MB). http://en.wikipedia.org/wiki/IBM_305 Somebody needs to fix the Wiki. It was 7 bits (remember the "odd parity"?) The bits are 1, 2, 4, 6, A, B and parity. It goes with "7 track tape" etc. The most popular military teletype machines (Mod 28 ASR33) were 7 bit ASCI with an 8th parity or "stop" bit. Eisboch Eisboch This wasn't ASCII, it was Binary Coded Decimal. The problem with even parity is a "blank" is even. All IBM machines used some varient of BCD before the 360 and "hex" That was a typo above bits are 1, 2, 4, 8, A, B parity. I think the confusion here is comparing the Teletype machines and the IBM machine. The Teletype Model 28 is 5 bit baudot and the Teletype Model 33/35 is 8 bit ASCII. |
1956 IBM hard drive
On Wed, 5 Dec 2007 08:52:20 -0500, "D.Duck" wrote:
I think the confusion here is comparing the Teletype machines and the IBM machine. The Teletype Model 28 is 5 bit baudot and the Teletype Model 33/35 is 8 bit ASCII. That's my recollection also. The model 28s used a "mode shift" key or some such to effectively double the character set. If the "mode shift" code arrived garbled, the receiving machine would miss everything that followed and print gibberish. |
1956 IBM hard drive
"Wayne.B" wrote in message ... On Wed, 5 Dec 2007 08:52:20 -0500, "D.Duck" wrote: I think the confusion here is comparing the Teletype machines and the IBM machine. The Teletype Model 28 is 5 bit baudot and the Teletype Model 33/35 is 8 bit ASCII. That's my recollection also. The model 28s used a "mode shift" key or some such to effectively double the character set. If the "mode shift" code arrived garbled, the receiving machine would miss everything that followed and print gibberish. For such a mechanical contraption, they were amazing. http://video.google.com/videoplay?do...544&q=mod-tage Eisboch |
1956 IBM hard drive
"Eisboch" wrote in message ... "Wayne.B" wrote in message ... On Wed, 5 Dec 2007 08:52:20 -0500, "D.Duck" wrote: I think the confusion here is comparing the Teletype machines and the IBM machine. The Teletype Model 28 is 5 bit baudot and the Teletype Model 33/35 is 8 bit ASCII. That's my recollection also. The model 28s used a "mode shift" key or some such to effectively double the character set. If the "mode shift" code arrived garbled, the receiving machine would miss everything that followed and print gibberish. For such a mechanical contraption, they were amazing. http://video.google.com/videoplay?do...544&q=mod-tage Eisboch Still remember the first KSR-33 I ever saw. Was working in the Western Electric Warehouse when the forklift operator got a pallet with one off the top of the storage racks. Someone had not strapped down the unit, and the top of the rack must have been 25' in the air. That KSR33 nosedived to the floor and parts went everywhere. Later when I had to work on the Teletype that NCR used as the console writer on the later Century systems, I wanted to drop more of them 25'. They used the light duty model, forget the number, that was designed to receive 3-4 messages a day and only turned on when a message came in. NCR ran them 24/7 and the shafts eventually were cut almost in half by the oillite busings wearing out. |
1956 IBM hard drive
"Calif Bill" wrote in message ... "Eisboch" wrote in message ... "Wayne.B" wrote in message ... On Wed, 5 Dec 2007 08:52:20 -0500, "D.Duck" wrote: I think the confusion here is comparing the Teletype machines and the IBM machine. The Teletype Model 28 is 5 bit baudot and the Teletype Model 33/35 is 8 bit ASCII. That's my recollection also. The model 28s used a "mode shift" key or some such to effectively double the character set. If the "mode shift" code arrived garbled, the receiving machine would miss everything that followed and print gibberish. For such a mechanical contraption, they were amazing. http://video.google.com/videoplay?do...544&q=mod-tage Eisboch Still remember the first KSR-33 I ever saw. Was working in the Western Electric Warehouse when the forklift operator got a pallet with one off the top of the storage racks. Someone had not strapped down the unit, and the top of the rack must have been 25' in the air. That KSR33 nosedived to the floor and parts went everywhere. Later when I had to work on the Teletype that NCR used as the console writer on the later Century systems, I wanted to drop more of them 25'. They used the light duty model, forget the number, that was designed to receive 3-4 messages a day and only turned on when a message came in. NCR ran them 24/7 and the shafts eventually were cut almost in half by the oillite busings wearing out. That 300 Megabyte DEC drive the RM05 was a CDC build drive. The RM03 was a smaller version. When I was an engineer for System Industries we sold the drive as a CDC 300 MB drive and disk controllers that looked just like the DEC controllers software wise. Plus we could hook several systems up to the same controller for shared data. |
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