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Author here for all your Nanoprocessor questions. It's an unusual processor, lacking the ability to add or subtract. Even so, it was used in HP equipment, not j
by kens 6y ago
Author here for all your Nanoprocessor questions. It's an unusual processor, lacking the ability to add or subtract. Even so, it was used in HP equipment, not just as a controller, but parsing strings and doing calculations.
- Zenst 6y agoThe whole aspect of each chips voltage being so variable that they had to test them and hand wrote the operating voltage, making any use of the chip down to matching that voltage - certainly making drop in replacements interesting for repairs. Then the last number on the chip to indicate speed. All that hands on for each chip and selling for $15 at that time - makes you wonder how much they made upon them with all that manual binning needed. Any idea on the margins back then for this chip?
- kens 6y agoSince the chip was used in HP products, there wasn't a margin as such. Much of the benefit was that they weren't paying margin to another company. As for repairs, each product's service manual has a table specifying the correct resistor value for each Nanocomputer bias voltage. So you'd need to change the resistor if you replaced the processor.
- kencausey 6y agoKeep in mind that $15 USD in 1974 is more similar to $80 USD today. So budget appropriately.
- gumby 6y agoDid they sell it on the open market or was it an in house device?
- formerly_proven 6y agoThanks for doing this, I remember a stumbling over this mystery controller in some piece of HP equipment I bought and at the time there was basically zero information about these around.
- myself248 6y ago> The Nanoprocessor supports indexed register access, but lacks the complex addressing modes of the other processors. It wouldn't have much use for complex addressing modes, given the lack of RAM, no? I'm trying to get my head around a RAMless computer and I'm not quite sure this all makes sense just yet.
- kens 6y agoIf you can do everything in 16 registers, you don't need RAM. You have to get in the mindset of a control processor application, doing things like reading buttons on a piece of HP test equipment or sending bytes over the network. You're probably just dealing with a couple of values at a time and don't need RAM. This is a completely different set of applications from a typical computer. As far as addressing modes, the Nanoprocessor has two modes for accessing registers. The first is direct, e.g. store the accumulator in register #3. The second is indexed through R0. Store the accumulator in register # (3 OR R0). This lets you do table lookups (in a small table). Adding to R0 would make more sense, but the Nanoprocessor doesn't have an adder so they use OR. So it makes sense to have multiple addressing modes even without RAM, but there's not a whole lot you can do with them.