The price of memory – Hardrives in 1980

The first hard drive I purchased for a customer was in 1981. The drive capacity was 80mb (yes that’s 80 megagbytes or 80*1024×1024 bytes, not gigabytes or terrabytes) and cost $18,000 USD.

The customer was the MATRE Hospital at Waratah NSW, Australia and the system recorded 12,000 microbiology lab results per month recorded in the Hunter Valley of NSW (population 500,000).

The hardware was a 6 user system comprising 6xDec VT100 terminals accessing a concurrent DOS processor running 6xZ80 CP/M processor boards storing data on the 80mb drive. The drive unit measured 90cm x 90cm x 90cm including the power supply unit an comprised 8 x 18″ platters and sounded like a 747 taking off when the hard-drive was powered up.

The hardisk drive cost $18000 USD with a unit price or $230,000 per gigabyte. Compare that to a modern 4GB USB memory stick at $4 USD in today’s prices and the 1980 hard-drive was nearly one million times more expensive and a million times larger. 

Was the system reliable?      Yes, except for Tuesday mornings when invariably the system went offline over night and data need to be recovered. After extensive investigation, it turned out that a cleaner came in Monday nights and turned off the hard-drive to connect the vacuum cleaner and then re-powered the hard-drive when finished. Result – data integrity issues and half a day lost per week and poor confidence in the system until the culprit was revealed.

Prior to the availability and relative convenience of hard-drives, the typical configuration I sold to customers was a single user 8bit Z80 processor with 64mb of dynamic RAM running CP/M operating with 2 x 1.2 mb 8″ floppy drives (in the late 1970s, single sisded floppy drives were 600mb each) . Drive A typically stored the operating system (which loaded into 32mb of RAM) and the application (typically compiled MSBASIC loaded into the remaining 32mb of RAM) and drive B stored the application data records. An invoice record was typically 60 to 120 bytes of data.

Sometimes the data would not fit on one 1.2mb floppy drive and  the customer was required to swap floppy drives. Purchase orders or customer orders were stored on one B: drive floppy disk and was the operator was requested by the application to remove the floppy in B: drive and swap it with the floppy that stored the debtors, creditors and general ledger data on another physical floppy disks when the order was complete.

The early days were challenging to say the least. By the way, I sold 3 of these systems each month at around 40% gross profit with a 2 man business returning $40k profit per month. Can you do that today?

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