What happened to the HEC Computer?
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- čas přidán 10. 11. 2023
- Get latest update on the HEC at:
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I understand that many people are concerned with the development of the HEC, and indeed it had hit some major roadblocks. But I decided to bring it back on the table with a narrower scope, now with better communication! - Věda a technologie
Please never give up! Even with ideas "much more crazy than yours" there will be people who are interested. Just it takes time to push through the barrier of the usual attitude of people "well, interesting, but I wait till it's something already other than just an idea which may not become the reality anyway - even if it's a cool idea right now". Yes, sometimes it's hard, I also felt (mainly with software development though) that I am seriously under-motivated, because no one is interested. But it turned out it was rather the case of "waiting" from people before showing/expressing their interest because being in doubts if it takes any form at all.
Glad to have you back Andy. Don't get discouraged by people's lack of awareness in the project. Not only do we want to see a working proof of concept, but I know this would eat away at you if you gave up on it completely. So don't just do it for us, do it for you! All the best.
Your English is fine, man. It improved a lot from the first Z80 multitasking video. I listened your first video just an hour ago and you can hear the clear difference.
I once had a time - might it have been 1995 - where i got hands on a book just explaining how to do a timer driven task switcher for the Z80. so i knew that a long time ago people were able to run sort of a multi-tasking OS setup on the Z80. please excuse that i am not sure if these solution was using just a timer interrupt or "wired" those timer to the Z80s NMI. but the key was that the used interrupt was able to offload sufficient registers so that all other states could be exchanged from task A to task B (and maybe even more). when returning from IRQ the task switch was seamlessly complete. in effect it was a time slicing multitasking for custom programs. no extra hardware required - just a bit of glue software to get it up and running.
(slightly different story: about the same time, meaning shortafter, i did wiring a PC card so that an NMI signal could be triggered up to some 10 kHz by a freely tunable function generator on a Windows PC. with the right "driver" software i was able to serve that interrupt and pull a few bits that i could monitor with a scope for success confirmation. if tuned towards a machine created IRQ limit rate the machine got irresponsive and could see recovery if not hold to long in that state but would finally freeze if clock went to high or hold for to long on the edge interrupt rate. - the whole job here was about finding out if some real time control would have been possible to get added - or being bought from a 3rd party as an add-on, or if such a PC like processor system in principle can do that to a sufficient degree of service, so that some other option for an embedded slot/card PC is trustworthy enough to have user and privileged code co-exist in the desired fashion.)
rationale: there is much feasible with simple logic but also as well without external circuits by pure software. its just the thing that either you need to have some "OS" on your own and also programs on your own, or you need some way to insert your tweaks like i did in the 2nd case with this tiny driver.
Now I really want to know what the bug was in the original design! For me this is one of the most interesting projects for the z80 on CZcams, and certainly the most original. As well as the neat idea itself, it provides a fascinating window on to the whole idea of a protected mode, how they work, and how to possibly implement one on the 8bit architecture we all know so well. Also, unedited videos are fine imo, as you make things very clear without edits, with this content it is the ideas that are important. Anyway, I'm just saying the obvious! Welcome back!
If a program is accessing a protected segment, hasn't it already crashed? If for some reason you did want to restart the program, what if every program on the system had to implement a 'restart' function at a given offset from its start location - then the controller swaps that location onto the address bus instead of the NMI return address?
Are you going to write an 8 bit OS that does switching so you can take advantage of this? A sort of Windows 1.0 but maybe with different look and feel?
I'm subscribed just for this 😂
Glad you've returned
Snazzy shirt...
What the HEC took you so long 😂😉
I will soon make a video about that!
@@andyhu9542 - that gives me a big reason to subscribe!