JWColby
jwcolby at colbyconsulting.com
Wed Jan 17 13:31:24 CST 2007
CPM? Newcomer! In 1972 the US Navy trained me to fix computers. The "trainer" was a 12 bit wide instruction with 512 words (12 bit) of CORE memory. You loaded the computer program in via spring loaded switches with light bulbs inside of them, loading machine language instructions and data into a register. The contents of that were transferred to a core memory location when you pressed a "store" switch. To SAVE the program you loaded a roll of paper tape onto a tape reader / punch and then the machine would punch holes into the paper tape. You would carefully roll the paper tape up and carry it around with you since you could then read that paper tape back into the machine if you wanted to. The trainer ran at the startling speed of 125 K instructions per second. I learned to fix that (and subsequent machines) down to the transistor level, though in fact we just replaced the entire little card, each card would have a flip-flop or a couple of and gates. It took entire rows of cards just to build up a register. My first personal computer was an "s-100" based Z-80 machine with 24K bytes of static ram. When I bought the computer it came with "zapple basic", which when I look at the name makes me think perhaps it was a z-80 translation of an apple basic language. At any rate, the interpreter was 12K so I had 12K free for my program. Zapple basic came on a cassette (the music kind) and I connected my stereo cassette deck to the board to load the program. IIRC it used a serial data stream at 300 baud to read from the cassette tape. At any rate, it took over 3 minutes to load Zapple Basic into the computer. Once that was done I used a dumb terminal on a serial port to display the programming prompt and the terminal's keyboard to type in my program. BTW I BUILT all of the boards in the system from kits I ordered from advertisements in the back of Popular Electronics, this was about 1977. Yep, with a soldering iron and schematics. In about 1982 I built my first REAL personal computer, a "single board computer" (SBC) from a kit. It used the 80186 uP at an incredible 16 MHz clock and had room on the board for 256K bytes of dynamic ram. By placing another dynamic ram chip on top of the first, carefully bending up the RAS pin of the dynamic ram, soldering all the remaining pins to the ram chip below, and then running a wire from the bent up pin down to a pad on the board, I "piggy backed" the memory and doubled my ram to 512 Kbytes. This SBC had 2 serial ports and a built-in floppy disk controller. For about $700 I purchased a dual 8" floppy drive, each drive could store 1 mbyte. This computer ran CPM-86. I purchased a 1200 baud modem which attached to one of the Serial ports, and since at that time I worked for a graphics terminal company called Megatek, I scrounged an old color graphics terminal which I attached to the other serial port. A REAL computer. I then purchased a Pascal compiler from a brand new startup by the name of Borland and I was on my way to a successful (?) programming career. Until 1986 I continued to fix electronics for a living, but eventually I switched to programming in around 1986 and never looked back. In 1987 I purchased my first brand name assembled computer from Epson of all companies, a 80188 running at 12mhz (PCXT clone) running DOS, with a 5gb disk drive and 2 mbytes of ram (1 on the MB and an add-on card for EMS). BTW, the only other preassembled computer I ever purchased was a 20mzh PCAT clone in around 1989. From that point on I purchased parts and just kept upgrading. I still buy all my components and build my own boxes. My most recent server is a dual core AMD with 4gb ram and a 2 terabyte raid6 array. In about 6 months I will be building a machine using a dual cpu motherboard (the AMD 4X4) using the quad core CPUs from AMD, which HOPEFULLY will be available by mid summer. Eight cores on a motherboard. That should make a fine SQL server for the big database I am working on. In 1984 I DREAMED of owning a VAX 11760 with 2 mbytes. Now I have a machine (in fact several) that is a thousand times more powerful, all that power being sucked up by Windows. ;-) John W. Colby Colby Consulting www.ColbyConsulting.com -----Original Message----- From: accessd-bounces at databaseadvisors.com [mailto:accessd-bounces at databaseadvisors.com] On Behalf Of Charlotte Foust Sent: Wednesday, January 17, 2007 12:15 PM To: Access Developers discussion and problem solving Subject: Re: [AccessD] [OT] OMG!!!!!! DOS?? Newcomer! I started with CP/M and loaded the bootstrap from a tape recorder! LOL Charlotte Foust -----Original Message----- From: accessd-bounces at databaseadvisors.com [mailto:accessd-bounces at databaseadvisors.com] On Behalf Of Susan Harkins Sent: Wednesday, January 17, 2007 9:05 AM To: 'Access Developers discussion and problem solving' Subject: Re: [AccessD] OMG!!!!!! I remember loading DOS because there WAS no hard drive -- do I win? :) Susan H. My first box had a 20 mb drive and I remember being told I could run a small business on that. -- AccessD mailing list AccessD at databaseadvisors.com http://databaseadvisors.com/mailman/listinfo/accessd Website: http://www.databaseadvisors.com -- AccessD mailing list AccessD at databaseadvisors.com http://databaseadvisors.com/mailman/listinfo/accessd Website: http://www.databaseadvisors.com