Possible idea surrounding x16 and x8 discussion

Sisko · Post by **Sisko** » Sat Oct 16, 2021 5:55 pm

I know this is complicated and I'm nowhere near the expertise, but out of all curiosity around what people think will happen with the x8 gets released (that all program development will focus on the lowest capable device), but is that not a concern with each phase of the base x16, Or is there such a leap in specs that I don't understand?

Please know this is more of a topic of discussion, and maybe a way for me to learn more about the technical side of these computers while throwing a bone of a idea from my head.

BruceMcF · Post by **BruceMcF** » Sat Oct 16, 2021 5:57 pm

On 10/16/2021 at 1:55 PM, Sisko said:

I know this is complicated and I'm nowhere near the expertise, but out of all curiosity around what people think will happen with the x8 gets released (that all program development will focus on the lowest capable device), but is that not a concern with each phase of the base x16, Or is there such a leap in specs that I don't understand?

Please know this is more of a topic of discussion, and maybe a way for me to learn more about the technical side of these computers while throwing a bone of a idea from my head.

All we know right now is that the X8 in its original form will not be released. Whether there will be a release in the X8 style that is more compatible with the X16, whether that would be before, alongside or after the first of the X16 boards released ... we simply do not know and any guesses would be speculation.

Sisko · Post by **Sisko** » Sat Oct 16, 2021 6:02 pm

On 10/15/2021 at 3:03 PM, Scott Robison said:

On 10/16/2021 at 3:57 PM, BruceMcF said:

All we know right now is that the X8 in its original form will not be released. Whether there will be a release in the X8 style that is more compatible with the X16, whether that would be before, alongside or after the first of the X16 boards released ... we simply do not know and any guesses would be speculation.

I understand, I was just thinking about the post they made and one of the concerns that they raised, I just had a thought and wanted to put the thought out there.

BruceMcF · Post by **BruceMcF** » Sat Oct 16, 2021 6:17 pm

The phases in particular were:

the mostly DIP chips including all of the glue logic chips as "phase 1", aka X16p (informally, "pro").

the cost reduced version of the X16p, surface mount chips where available, possibly a single SRAM, only one or two slots, maybe with a CPLD replacing the glue logic if it brings enough cost reduction, as "phase 2", aka X16c (informally "compact", even more informally, "cost reduced")

the version that brings as much as practicable into an FPGA (likely an upgrade on the Vera FPGA), without slots, possibly without User Port, "phase 3", aka X16e (which I prefer to think of as "embedded processor")

Swinging the X16e to the first release or alongside the X16p release means we would REALLY need to drop the already confusing "phase" language, since saying something like "we are going to release Phases 1 and 3 side by side, and if they are successful we will then release Phase 2" is completely and totally confusing to anything who wasn't been following the project closely.

An option without a name, but with could be called the "X16jr", would be to do something along the lines of the X8 but with a memory map and I/O memory location more closely compatible with the X16, allowing plug and play sharing of binaries that happen to fit within the tighter memory constraints of the "X16jr".

TomXP411 · Post by **TomXP411** » Sat Oct 16, 2021 7:25 pm

The X8 is really a different beast than the later stages of the CX16 roadmap, so the X8 debate won't be one with the FPGA or SMT versions of the CX16.

With the X8, you're talking about a computer that's really very different: it will not have a full ROM. Instead, it will have a bootstrapped RAM operating system with a very small bootstrap ROM. This is how CP/M works: there's just enough ROM (a single page, in fact) to boot the BIOS from disk. Then the BIOS boots the command processor, and you have an operating system. From what I understand, the CX8 will work similarly: the bootstrap ROM will load a BASIC+KERNAL program from SD. This means that programs can be written to occupy all 63K of system memory (There is a small carve out for I/O space) without ever actually loading the KERNAL or BASIC. This is not something the CX16 is currently capable of (unless we get RAM in one of the ROM banks.)

The other difference is that VERA is accessed via a single, 256 byte page, rather than the 32 I/O registers we have now. This dramatically changes the I/O process, since you have access to a full line of text or tiles directly, rather than the indirect method the CX16 uses.

And we obviously have the 512K vs 128K issue to think about. Programs written for the CX8 will have to fit no more than 128K: 64K of main memory and 64K of video memory.

On the other hand, the Commander X16 roadmap includes a Surface Mount (SMT) version and an FPGA version. Both of those will have the same I/O and memory structure as the CX16E (the version currently in the works), but with smaller circuit boards and fewer chips to do the same job. While the package may be smaller, the software will be the same: the same program will run, unmodified, on all 3 of the planned Commander X16 editions. Software that directly accesses video, sound, the User port, or the IEC bus will not run unmodified on a Commander X8.

That's the difference. The X8 is a different computer, and while it shares some common parts, it's as different from the CX16 as the Commodore 64 was from the Plus 4.

Ju+Te · Post by **Ju+Te** » Sat Oct 16, 2021 7:29 pm

Why not use clear, easy to memorize and understand names like X16-DIP, X16-SMD and X16-FPGA?

BruceMcF · Post by **BruceMcF** » Sat Oct 16, 2021 7:37 pm

On 10/16/2021 at 3:29 PM, Ju+Te said:

Why not use clear, easy to memorize and understand names like X16-DIP, X16-SMD and X16-FPGA?

Don't know.

Of course, there's going to be some sticklers who would be all "not ALL of the chips in the X16p are DIP, not ALL of the chips in the X16c are surface mount, all three boards HAVE an FPGA". Iron Internet Law number 38 is "no naming satisfies everyone".

rje · Post by **rje** » Sat Oct 16, 2021 8:26 pm

On 10/16/2021 at 2:25 PM, TomXP411 said:

From what I understand, the X8 will work similarly: the bootstrap ROM will load a BASIC+KERNAL program from SD.

Aha, that's interesting. I had thought that it would bootstrap from one of those supercheap slow-ROM thingies. Rats, I forgot the name.

Well anyway. Booting from SD is certainly more modern, and very flexible!

BruceMcF · Post by **BruceMcF** » Sat Oct 16, 2021 10:42 pm

On 10/16/2021 at 4:26 PM, rje said:

Aha, that's interesting. I had thought that it would bootstrap from one of those supercheap slow-ROM thingies. Rats, I forgot the name.

Well anyway. Booting from SD is certainly more modern, and very flexible!

Given that the bootloader is 512bytes, power-up interrupt vectors included, so I supposed that it would be booting off the serial flashROM, with the Kernel that it loads containing the code to read the SD card. But that was just supposition.

paulscottrobson · Post by **paulscottrobson** » Sun Oct 17, 2021 8:52 am

On 10/16/2021 at 6:55 PM, Sisko said:

I know this is complicated and I'm nowhere near the expertise, but out of all curiosity around what people think will happen with the x8 gets released (that all program development will focus on the lowest capable device), but is that not a concern with each phase of the base x16, Or is there such a leap in specs that I don't understand?

Please know this is more of a topic of discussion, and maybe a way for me to learn more about the technical side of these computers while throwing a bone of a idea from my head.

They're very similar. In some ways the X8 is actually better.

The shortfall in the X8 is RAM memory (and expandability, but that doesn't affect software so much). I'd say it was likely that a machine with the X8 level of specification would load code and graphics off Smartcard rather than holding it in SRAM, would probably not use much in the way of direct sound (though this is an X16 issue as well) and would be more likely to use 4 bit colour rather than 8 bit colour and/or have a lower resolution.

It's backwards to the Plus4/16 issue really, they had identical hardware but much less program RAM. The X16 has more banked storage, but both systems have the same basic memory space.