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Author Topic: SymbOS (Read 616669 times)

Offline Zozosoft

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Re: SymbOS
« Reply #30 on: 2014.October.12. 13:29:39 »
The SD interface have a memory mapped I/O, and also own RAM space both in the ROM segment. For accessing need to be the ROM segment paged in, because the I/O space.
Anyway the ROM section (the first 8k) of this special segment also can be paged (total 64K, 8*8K pages), then possible put the SymbOS driver ROM to another part if the original ROM not enought.
« Last Edit: 2014.October.12. 20:51:01 by Zozosoft »

Offline Z80System

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Re: SymbOS
« Reply #31 on: 2014.October.12. 14:52:19 »
I do not understand a (many :)) thing ...

When somebody made a storage device in the past, it was an EXDOS EXTENSION device.

There is the IDE card from Zozosoft, what can use IDE devices like HDD,IDE-TO-CF Memory Card,or anything ... and this IDE card has an EXDOS EXTENSION interface towards EXDOS.
There is the cartridge SD card what is an EXDOS EXTENSION device, too.
Saint's combined SD solution was planned to be an EXDOS EXTENSION device, too.
And the original floppy drives, as well.

So when this OS would be ported to the EP, every single hardware device have to get a new driver, towards SymbOS ?

Afther that, making a hardware device will require making two drivers, one to EXDOS and one to SymbOS ?
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Offline Z80System

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Re: SymbOS
« Reply #32 on: 2014.October.12. 15:01:57 »
Does it mean, that SymbOS uses everything with hardware level access ?

And would it not be interactions between EXOS and SymbOS ?

For example, there will not be a command prompt in SymbOS where we can do EXOS EXTENSION calls ?

On EPs, what have EPROM EXOS EXTENSIONS, those EPROMS will be unavailable from SymbOS ?

SymbOS will use EXOS probably only for startup ? After that, EXOS will be erased from memories, like the FF system segment, or such ones ?
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Offline Z80System

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Re: SymbOS
« Reply #33 on: 2014.October.12. 15:28:12 »
Probably it left out from the "news":

http://enterpriseforever.com/hardware/exp1-and-exp2-pinouts/msg34847/#msg34847

Somebody can easily get an internal 512K/1024K expansion from saint, what can be assembled in place of the original 64K expansion.
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Offline lgb

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Re: SymbOS
« Reply #34 on: 2014.October.12. 21:03:46 »
SymbOS will use EXOS probably only for startup ? After that, EXOS will be erased from memories, like the FF system segment, or such ones ?

Exactly. Why are you surprised, SymbOS is not an Enterprise-128 OS it needs only Z80, it has some memory requirements (with certain memory paging method) and not so much more to be able to port it to another machine: it also means that in theory SymbOS applications can run on any of the machines SymbOS runs. So It can't depend on any of the existing OSes, otherwise it wouldn't be portable too much. It wouldn't be true OS then either, as it would require another OS (EXOS) to be able to run :) SymbOS is a message-passing microkernel based multitasking OS, EXOS wouldn't even work this way at all, so it would be hard to interact.

That's one reason - I've told - that SymbOS is great but also, it means to lost "Enterprise specific" things (like EXOS/EXDOS), but everything has its own price ... To develop something GUI/window based but still EP specific thing would be more like EGI, and not SymbOS, they have quite different scopes.

Offline Z80System

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Re: SymbOS
« Reply #35 on: 2014.October.12. 21:09:12 »
Quote
, they have quite different scopes.

Yes, you are right, only it is strange ...

When one thinks of the EP then thinks of EXOS, too.
Everything was bounded to EXOS.
But with SymbOS we may have choice, using EXOS or SymbOS.

Multi - boot EP ... :)

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Offline Zozosoft

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Re: SymbOS
« Reply #36 on: 2014.October.12. 21:25:03 »
I think the best thing if the EXOS still accessible under SymbOS. Can be opened EXOS window like as EGI :-)
Then normal Enterprise programs can be started from SymbOS file manager.
Warm reset feature also only can be used when the system segment preserved.
If this is only work with memory expansion, don't problem. Todays very easy add megabytes to the Enterprise :-)

Offline Z80System

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Re: SymbOS
« Reply #37 on: 2014.October.12. 21:35:34 »
Quote
I think the best thing if the EXOS still accessible under SymbOS.

Probably Zozo you make the same mistake I did.

With SymbOS there is NO such thing that EXOS. EGI is an extension of EXOS. SymbOS (probably) replaces EXOS.
SymbOS uses the hardware, and all of it. SymbOS (probably) will not check memory segments allocated by EXOS. Its a standalone and different thing.
SymbOS's applications runs inside SymbOS. SymbOS is not a Current Application Program to EXOS, or probably only at its bootup.

So that would be a different effort to make SymbOS to keep EXOS intact.
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Offline Zozosoft

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Re: SymbOS
« Reply #38 on: 2014.October.12. 21:39:11 »
Do you read what I'm wrote? :oops: see the word: IF :twisted:

Offline lgb

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Re: SymbOS
« Reply #39 on: 2014.October.12. 21:52:12 »
I think the best thing if the EXOS still accessible under SymbOS. Can be opened EXOS window like as EGI :-)
Then normal Enterprise programs can be started from SymbOS file manager.
Warm reset feature also only can be used when the system segment preserved.
If this is only work with memory expansion, don't problem. Todays very easy add megabytes to the Enterprise :-)

That was what I suggested too. Let's SymbOS loader to allocate as many memory segments as it can, and what it can allocated, it's marked to be used by SymbOS, and already used segments (system segment, page 0 ...) would be untouched. There are few problems though:

* it won't run on base Enterprise-128 in this way, as SymbOS needs 128K RAM minimum. Remedy: if SymbOS loader can allocate more segments than 128K in sum, let's use only those, otherwise let's use the whole RAM. Still, if video RAM is needed and not enough segments can be allocated, that's a problem (possible solution with enough RAM expansion: let's SymbOS to copy already used segments like system segment into a normal one, and copy back on request but it would be a problem with warm reset)
* since SymbOS uses direct hardware access, the state of eg WD chip can be undefined and not what EXDOS would expect
* normal enterprise programs could be launched though, but it would need to have Enterprise-128 specific part in SymbOS userspace or at least some "loader" ... Also then SymbOS would need to re-free some segments for the app?
* it wouldn't be so much possible easily to return to SymbOS from Enterprise app, maybe the warm reset sequence but basically it means "restart" thus other running apps are lost inside SymbOS
* of coure multitasking is disabled during executing Enterprise-128 app, basically it would mean to pass the full machine back to EXOS from SymbOS

I think it's even more easy (but that is also hard!) to write a new EXOS which allows some kind of "multitasking" even if it only means to "switch" between running apps, and not running them in parallel as with true multitasking OSes

Offline Z80System

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Re: SymbOS
« Reply #40 on: 2014.October.12. 21:54:13 »
Quote
Do you read what I'm wrote? :oops: see the word: IF :twisted:

Thinking a little, maybe it is only a not too much modification of the memory handling of the SymbOS ...

Using only segments not allocated by EXOS ...

But I am not sure, it is worth the effort.




And I think it would not be only the memory handling ...

For example, making exos extension calls:

:help maybe could run ...

but :dir will interfere with the hardware device handling of SymbOS ... so ... probably such thing is not easy ...
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Offline lgb

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Re: SymbOS
« Reply #41 on: 2014.October.12. 22:08:15 »
:help maybe could run ...

but :dir will interfere with the hardware device handling of SymbOS ... so ... probably such thing is not easy ...

Still I can't see the advantages especially compared the difficulties it would mean to implement this. Even running a simple help command would require to partly switch back normal EXOS memory (system segment, etc) and shutting down SymbOS IRQ, RST vectors etc so basically stop its working while command is running. Otherwise it would be problematic that SymbOS uses the RST vectors EXOS would also use, and other problems like this. It someone only wants to use SymbOS as a "file browser" to run non-SymbOS (like Enterprise-128) applications, it's a bid odd to do :) It would be still possible to develop an OS like entity sitting on the top of EXOS with even multitasking (from EXOS side it's a single app) but it wouldn't be SymbOS, and really "hard" multitasking nature would be problematic because of the EXOS mono-tasking nature (thus a disk I/O would hang multitasking - but anyway, pseudo OSes - like Win95 was, basically it's something runs on the DOS halfly not a stand-alone OS - as far as I know it still used BIOS to acces floppy drives thus making serious hangs when dealing with floppies ...).
« Last Edit: 2014.October.12. 22:12:16 by lgb »

Offline Z80System

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Re: SymbOS
« Reply #42 on: 2014.October.12. 22:11:43 »

Quote
Still I can't see the advantages especially compared the difficulties it would mean to implement this.

Yes, probably it is the closest to the truth ... :)
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Offline lgb

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Re: SymbOS
« Reply #43 on: 2014.October.12. 22:17:40 »
Yes, probably it is the closest to the truth ... :)

One intersting though VERY MAD project: implement a new, EXOS which runs as a SymbOS application :-P Especially having IS-BASIC as SymbOS app would be funny :) Normal EXOS programs using strictly EXOS functions may work somehow (though I no idea how to cure problems like conflicting the usage of RST vectors), but even just trying bother B0...B3 ports to do memory mapping would cause a crash I guess :( Or such.

Regardless of SymbOS, I had the odd idea to really write a new EXOS (not just "binary patching" existing, original EXOS) which is as much compatible with the original as possible but introducing new features like having muliple programs as same time and allow to switch between them (well, with enough RAM it's not so impossible, some just may need to backup/restore system segment and page0, etc, I am not sure if it's really possible). But this is again a project which would not to worth to really do, as the this is hard to do ...

Offline Z80System

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Re: SymbOS
« Reply #44 on: 2014.October.12. 22:19:57 »
Quote
One intersting though VERY MAD project: implement a new, EXOS which runs as a SymbOS application

It would be some kind of OS virtualization, isn't it ?

SymbOS host EXOS guest ... :)
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