[HN Gopher] Running CP/M on the Raspberry Pi Pico
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       Running CP/M on the Raspberry Pi Pico
        
       Author : _Microft
       Score  : 42 points
       Date   : 2022-03-27 14:52 UTC (8 hours ago)
        
 (HTM) web link (kevinboone.me)
 (TXT) w3m dump (kevinboone.me)
        
       | butlerm wrote:
       | > CP/M predates the open source movement by thirty years.
       | 
       | CP/M was first developed in 1974, the FSF was founded in 1985, so
       | I would say more like eleven years.
        
         | johnklos wrote:
         | Beyond the FSF, Berkeley released sources to BSD as open source
         | throughout the '70s.
        
       | ahepp wrote:
       | > CP/M programs often behave in ways which would be damaging to
       | modern hardware -- endless input-checking loops at full CPU
       | speed, for example. To be honest, I do not know if this kind of
       | thing would be damaging to a Pico, but I don't want to risk it.
       | CPICOM has a number of pause points built in, to give the
       | microcontroller time to idle. These do slow the system down even
       | further, and I'm not sure whether they're necessary.
       | 
       | This shouldn't be necessary on an MCU. Any kind of sleep call is
       | probably just spinning the CPU anyway. There's often support for
       | deeper power saving states, but MCUs are generally designed to be
       | run full speed all the time.
        
         | mistrial9 wrote:
         | its my understanding that you cannot damage the physical CPU by
         | software instructions, period. However, heat from multi-core
         | operations is not the same. Hardware gets damaged by heat all
         | the time. So "loops waiting for input" may never damage the
         | hardware, but "causing more cores to operate at the same time"
         | can cause heat damage on some setups..
        
         | jstanley wrote:
         | I don't think busy loops are _damaging to the hardware_. They
         | just pointlessly waste CPU time.
        
         | spc476 wrote:
         | There are CPUs out there that can be put into a "sleep" type
         | mode. On the x86, there's the HLT instruction, which stops CPU
         | execution until an interrupt happens. The 68k series has the
         | STOP instruction, which does the same thing.
        
       | pmontra wrote:
       | > if the ZX80 could generate a video signal from its CPU while
       | still running BASIC programs back in 1980,
       | 
       | It couldn't. The ZX81 could.
       | 
       | https://www.sinclairzxworld.com/viewtopic.php?p=20645&sid=86...
        
       | johnklos wrote:
       | The chain certs expired last September.
       | 
       | https://www.ssllabs.com/ssltest/analyze.html?d=kevinboone.me
       | 
       | Preservation is always good, and some of the software from the
       | CP/M world can be quite useful.
       | 
       | People can use constant reminders that software can be good
       | without taking gigabytes of memory for the most basic of
       | functions. We can literally emulate an entire computer and run
       | its OS and software faster and more efficiently than we can
       | render a page in a web browser.
       | 
       | Small and efficient is good :)
        
         | kjs3 wrote:
         | Indeed. You can go a very, very long way in productivity with
         | Wordstar, Visicalc and Turbo Pascal on CP/M, each of which fit
         | on a floppy. Many of us did.
        
           | Sunspark wrote:
           | Back when everything was new for the first time.
        
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       (page generated 2022-03-27 23:01 UTC)