According to [MTSI], if you used a Z80 chip back in the 1980s, it almost certainly passed through the sole Fairchild Sentry 610 system that gave it the seal of approval.
The Sentry was big iron for its day. The CPU was a 24-bit device and ran at a blistering 250 kHz. Along with a tape drive and a specialized test bed, it could test Z80s, F8s, and other Mostek products of the day. There was a disk drive, too. The 26-inch platters stored under 10 kilobytes. Despite the relatively low speed of the CPU, the Sentry could test devices running up to 10 MHz, which was plenty for the CPUs it was testing. The actual test interface ran at 11 MHz and used an exotic divider to generate slower frequencies.
According to the post, an informal count of the number of chips in the device came up with around 60,000. That, as you might expect, took a huge power supply, too.
From some 1975 corporate literature:
“Optimized for engineering, sophisticated production needs, QA and test center operations, the Sentry 610 is the most versatile analytical tester available for engineering and production. It can perform the widest range of tests for the broadest range of components. At user option, the Sentry 610 can perform high-speed MaS/LSI, PCB, and bipolar tests simultaneously. It offers complete testing at the wafer level and through automatic handlers at full-rated device speeds up to 10 MHz. The wide choice of peripherals gives the Sentry 610 system massive data handling capacity to manipulate, analyze, compute and generate reports on test procedures in analyzing MaS/LSI.”
These days, you are as likely to stick test hardware on the IC as have a big machine on the outside. And even then, you probably wouldn’t have something this elaborate. But in its day, this was high-tech for sure.
The Z80 sure has had a long lifespan. It shouldn’t surprise you that Z80s need to be tested, just like everything else.
And the price was ???
If you have to ask, you can’t afford it.
That would be a great way for Waitrose to save money, stop printing price labels and just take all of the customer’s money off them at the till; and if anyone enquires on prices, give them your answer along with the gentle suggestion that there is probably an Aldi or Lidl not so far away if they don’t like it.
From the article it links to.
It was introduced in 1971. It lived in a raised floor room. It had 60,000 IC chips, a mix of TTL and ECL. Looking at a July 20, 1970 issue of Electronics magazine,
https://www.worldradiohistory.com/Archive-Electronics/70s/70/Electronics-1970-07-20.pdf
Hm. Page 147/158 of the pdf shows a crisis in Europe. TTL has tumbled to 20 cents a gate in quantity. Now most of the TTL in that machine would be things like quad NAND gates and dual D flip flops. So 4 to 12 gates per chip, say $0.80 to $2.40 per chip. Even if all of the chips were TTL, that would push just the silicon cost to over $100k. But some of it was ECL. Later in the decade, when it was more common, it typically ran closer to $100 a chip, even for simple chips. Even at half that, it wouldn’t take much to push silicon costs alone to be a multiple of that $100k.
TLDR; not cheap.
You have to remember that this was probably bespoke test equipment. And for the semiconductor industry, no less. Probably not less than $1 million, I’d guess, for a nice round number. (Apologies, my estimate may be in mid-80s/early-90s dollars. BTW, There was 400% inflation between 1971 and 2006, the bulk of which was in the 1970s/early-80s)
Some other very interesting retro stuff at that linked site, like “We Picked Apart the Milestone HP-35 Calculator” https://mtsi.substack.com/p/we-picked-apart-the-milestone-hp
Mmm. Looks like the goodly grain of Tri-X.
The good old days. Slippery potassium solutions and the sharp tang of stop bath!
I don’t miss the smell of fixer on my fingers for hours after a stint in the darkroom though.
This.
To this day I can still recall the exact smell of fixer. It absolutely Would. Not. Wash. Off.
STM32F
ARM Cortex-M3 core at a clock rate up to 72 MHz.
The Flash memory for XL-density devices has density of up to 1 Mbyte, for other devices density of up to 512 Kbytes. …
Embedded SRAM feature up to 96 Kbytes of static SRAM.
SHILLEHTEK Pre-Soldered Authentic STM32F103C8T6 ARM STM32 Minimum System Development Board Module STM32F103C8T6 Core Learning Board.
$8.99
Can it run 64 bit floating point memory register technology programmed in transparent portable gcc c?
Now arriving today 12:45 PM – 2:45 PM
No discarded bits as in Nvidia AI 32 bit hardware floating point high power consumption accelerators. :(- –
Not in 1976 it didn’t!
We will laugh at the specifications of the STM32F in 48 years too!
Yes, as we tend from our campfires cooking our meager meals in pottery.
https://github.com/rejunity/z80-open-silicon
Regarding “These days, you are as likely to stick test hardware on the IC as have a big machine on the outside. And even then, you probably wouldn’t have something this elaborate. But in its day, this was high-tech for sure.”
It is true that many chips have (automatically inserted) test hardware connected internally using a serial JTAG “scan chain,” and indeed this is useful for finding static faults, but this is no substitute for testing chips at speed. For that you need expensive testers, which are almost always at the cutting edge of speed, employ wafer-scale probes, and are very expensive. Time on a chip tester is more costly than a phone call with a lawyer. The longer your chip is connected to the tester, the higher the “price tag” of your chip. So, to come full-circle, it does behoove the chip designers to include hardware fancier and faster than JTAG to help the expensive chip testerquickly test all the functionality of the chip and make sure it meets the speed specs at all four “corners” of the temperature-voltage range.
Pure speculation from someone who left the semiconductor industry just as voltage regulator started routinely appearing on chips: Aha! Maybe it is this four “process corners” testing issue that is one reason why. If you can guarantee that the chip’s internal power rails are always at one, carefully regulated voltage, then you only have to vary the temperature during testing, thus halving the time on the chip tester. Can anyone confirm or deny this?