640K of memory (RAM) is the maximum an Operating System called DOS could utilize - 25+ years ago...
No not the stuff called grey matter, the RAM in your computer.
When I think back to my first job as an entry level tech installing memory and configuring it to run properly in the IBM PC and IBM PC XT were some of the hardest tasks I had to do. Physically and mentally.
Note: 1KB is one Kilo Byte, 1 MB is one
Mega Byte. ( 8 Bits make 1 Byte or the space one character of the
alphabet would occupy in the memory of a computer.)
You see back in the day RAM came as a DIP IC (Dual Inline
Pin Integrated Circuit). They were about 1/4 of an inch wide and from 1/2 to 3/4 inch long. The pins were inserted in to a socket then pressed down until you heard a sound like a cracker crunching (not kidding!), when you heard the "crunch" you knew all the pins were seated and locked in the socket.
Think about dominos, if you have a box of dominos all lined up eight in a row side by side then eight rows that would be what a memory
array/card would look like. Some of the arrays/cards had 9 sockets (the ninth chip was a parity chip.
Parity was required on the original IBM motherboards because there wasn't any
memory management chip sets at that time.) in 10 rows. Each socket had to have a
RAM chip or DRAM as they were known. My thumbs hurt thinking of pressing in all that memory.
Then when you had the memory on the card you had to check a chart to set the dip switches to configure the
array/card for the type of memory the computer needed for the task it was to do.
Was the memory to be Expanded or Extended? Was there to be a Hi Mem area or all the
RAM one contiguous memory block?
And when you finished with all that work how much more memory did you add to
the computer? 256K to 2 MEG!
Quote a very rich man:
"You will never
need more than 640K of memory in a computer"
Oct. 18, 1985, COMDEX, Las Vegas, Nv.
When IBM introduced the PS/2 line of computers and Apple introduced the Macintosh a new type of memory was introduced: SIMM (Single Inline
four SIMMs had more than 640K of memory, 1024 K or 1 MB!
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Now this was cool, all the memory was soldered on a small PCB, no more DIP DRAM chips to press in to sockets. Just insert the memory module in the socket, make sure the little locking tabs on each end of the socket locked the SIMM in to place.
Now you need more than
640K of memory...
When Windows 95 came out all this "Memory Configuration" was supposed to end, it didn't, you just had more memory to play with.
By this time memory configuration was done with a chip set on the motherboard, the BIOS, and a "Memory Management Driver".
However the memory management driver didn't always work as advertised and you had to manually modify the system.ini file to tell the OS how much memory was in the computer, how much was base memory and how much was "Hi Memory".
By the time Windows NT 4 came out Microsoft had figured out how to make the memory management driver work reliably and the rest is history.
Now we have Gigs on a DIMM (Dual Inline Memory Module)
instead of Megs of memory and the chip sets in conjunction with the processor
control how our memory works, so our memory concerns are a bad dream. Or are
This little article shows that the Industry leaders, insiders, and Guru's
really don't know what the future will bring.