Comment by limbicsystem | Hacker News Reader

Comment by limbicsystem | Hacker News Reader

Old computer systems are fascinating from many points of view: The article discusses the software used to wring the last drop of performance out of hardware that we would probably now consider to be inadequate for running a disk controller. It's super cool that many of these systems are now available as emulators! I was a little surprised that the author only got twice the performance of the DtCyber in an emulator until I saw that they were emulating on an 800MHz P3 :)

In addition, visiting these old devices IRL is pretty instructive: one thing that always strikes me when I visit the Computer Sheds in Yorkshire (http://www.computermuseum.org.uk/ - an absolute gem BTW) is the enduring problem of thermal management. Up close, those old mainframes are basically huge air conditioning systems with some chips attached. My understanding is that managing heat is >still< the ultimate factor limiting performance (otherwise we could just stack up silicon in 3D)...

> My understanding is that managing heat is >still< the ultimate factor limiting performance

It seems fitting that I'm hearing the fans spin up to full blast on my ThinkPad X1 Extreme laptop supercomputer as I compile some code in an Ubuntu VM while starting up a CPU-hungry Point Of Sale system in a Windows VM, and reading your comment on the Windows host OS.

It is nice that I can step away from the computer and just listen for the fans to quiet down again to tell when everything is ready to go.

Are you monitoring temperatures on it?

Not specifically, but the top of the keyboard does get warm when all this is going on. Do you or anyone have any recommendations for temperature monitoring software for a ThinkPad running Windows with various other OSes in VMs?

In any case I think the POS software may be the main culprit, as it normally runs on a standalone machine and wasn't designed for power savings. I did set the Windows VM it runs in to "Power saver" but it doesn't seem to have helped much.

(Sorry if this is off topic for the thread!)

SpeedFan? https://almico.com/speedfan.php

Have you activated VT-x VT-d etc in the bios?

If not prepare for a performance boost, and a quiet Fan ;)

Thanks for the tip. Yeah, "Intel Virtualization Technology" and "Intel VT-d Feature" are both enabled by default in the BIOS (in fact it doesn't let you turn them off).

Ah ok, i have seen some bios's where both are deactivated plus hyper-threading too :)

NotebookFanControl is the only one that works on newer machines in my experience.

https://github.com/hirschmann/nbfc

I'm asking because I'm wondering how often it hits 99 degrees and throttles. And if it doesn't, I really need to take a closer look at it, because that would be incredible.

Dell and HP machines have this problem, 6 core Intel processors run slower than 4 core ones because the former always throttle (even though the TDP is supposedly the same).

If you want, you can use Throttlestop to set better controls/limits on clocks and power (and possibly undervolt it) for better performance, battery life and temperatures.

I'm using ArgusMonitor for this: https://www.argusmonitor.com

I don't have a thinkpad, but I like OpenHardwareMonitor for my computers: https://openhardwaremonitor.org/

Well, at least it's Thinkpad X1E...

We had much less going on when we joked that you know who is compiling or running any sort of serious work in the office by hearing whose MBP was whining hard with its fans.

Ah yes, these fans may get loud, but they are nothing like an office back in the day full of hackers on ASR-33 Teletypes!

Each one had a noisy keyboard and a noisy printer. The keyboard didn't have a nice click like a modern keyboard, more of a loud scrunchy sound. The printer was even louder and rang a bell if you had a line too long.

You could always tell when the mainframe crashed. Everyone's Teletype printer stopped all at once, and everyone started mashing down every key on their keyboard out of frustration.

Everything that is thin and light is going suffer from heat earlier than a bigger laptop.

Game laptops or workstation laptops are better solution(s) but the best is getting a desktop. I'm not joking and I'm aware of taking a device with you everywhere.

> hardware that we would probably now consider to be inadequate for running a disk controller.

Wasn't the disk controller chip in the BBC Micro significantly more powerful than the main CPU? I think some games used it as a coprocessor.

That's ludicrous. The 6502 is the best 8-bit processor that ever existed ;-)

Now, on a more serious tone, any processor in the machine you could detect could be used to offload some processing from the CPU. I wonder if that wasn't done with 1541 or 1571 Commodore floppy drives. I know there was software that wrote new functionality onto the drive's memory to make disk IO faster.

With enough memory, you could sort a text file and write the output to a new file without ever bothering the CPU. I don't think that was ever actually done, but the drives also ran 6502 processors, and the 1571 ran at twice the main computer's clock.

There's every chance I'm remembering it wrong - the double the clock speed certainly rings a bell. Got a weekly video call with a friend who still regularly hacks on a Beeb, so will try and clarify and update my comment tomorrow :)

The Beeb and the Ataris ran at 2 MHz. Apple II, VIC-20, C64, and 1541 all ran at 1 MHz. The 1571 ran at 2 MHz, same as the C128 (except when pretending to be a 64)

The beeb had an additional advantage: RAM ran at 4MHz, so the CPU and the video chip didn't have to compete for access.

Same for the C64... RAM at twice the Hz so the 6510 and SID/VIC-2 accessed it interleaved.

The 1571 was the drive meant for the C-128, which could also run at double speed (2 megahertz!) with the C-64 video chip disabled and the 80-column video running.

On the C64/1541 you could definitely upload code to one or more of the 256-byte 1541 disk buffers and make the drive execute it. The problem is you have 3 pins to transmit your data and those are not connected to any communication facility like an ACIA - you have no choice but to involve the CPU in some bit banging there.

The 1571 used the burst mode of the CIA IIRC (also IIRC it wasn't done in the 1541 to be compatible with the VIC20) so there were more possibilities there.

> The problem is you have 3 pins to transmit your data (...) you have no choice but to involve the CPU in some bit banging there.

Well... As long as the code takes longer to compute than it takes to push/pull the data, it's still a win.

I really can't think of any practical usage, of course. Maybe transforming ASCII files to EBCDIC ones without involving the CPU, or generating CRC32 values for the files on disk.

Did not fast loaders for the drive put a small program on the disk drive?

They did, but the CPU still has to manually manipulate the ATN, DATA, and CLK pins.

There's no I/O controller, just two "Complex Interface Adapter" which each have 8 I/O ports, readable/writeable by the CPU using standard LDA/STA, etc. instructions. (The CIAs also have a timer and can generate IRQs).

IIRC 3 bits from CIA #2 can set/read each pin state. The CIA won't do anything to those on its own at all.

I think there were plans to use something like IEEE-488 or GPIB but scrapped due to cost.

So you can definitely write a program to implement a faster protocol than the one in the Kernal/1541 ROM (e.g use DATA and CLK as data lines and use ATN to sync, doubling transfer rate), but the CPU will still need to be 100% utilized in the (shorter) transmission.

One thing you could setup on the Commodore drives is file copying from on drive to another without it going thru the computer, they just talked to each other. You could also do the same thing if you had a straight text file and sent it to the printer (I am not sure which printer models) with again not using the computer after the handshaking was set up.

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