I think it would have fared much better if I had waited until I got my ISA Ethernet card in the mail. But serving this over serial at 38400 baud and watching it try to keep up was tempting. I’ll have to see how well it fares with real networking hardware. At that point I might post it again, although I will have to add enough content to it to justify a repost.

Are you able to measure the latency of processing one request when there is no load?

Just back of the envelope, if it takes 200,000 instructions to handle a request and we assume 6 cycles per instruction, then that’s about 25 requests per second.

HN is roughly 50K requests over 6 hours, so that’s roughly 2 requests per second on average. I would imagine it peaks to about 25. So in theory you should be able to handle the traffic.

The 38400 baud might be the biggest bottleneck.

http://bettermotherfuckingwebsite.com/ is 20k, ignoring http overhead.

Maybe strip that to 15k after compression, and cut some content.

Still 15000/38400 <= 3 responses per second.

Add in serial parity overhead, http overhead. Might be able to sustain 2 rps with enough cleverness.

Leaves no room for bursts

Don’t forget that 38400 baud serial is 3840 bytes/s…

38400 baud should be 38.4kbits/sec or 4800 bytes/sec no?

[edit] never mind, you're right, assuming an 8N1 configuration - 8 bit bytes, 1 start bit, 1 stop bit, and no parity bits.

Yup definitely forgot bits vs bytes lol.

So 3kB/s, if your site is 15kB you're looking at 5 seconds per request, or 0.2 rps.

Plus overhead. I thought my original math sounded too fast.

A nitpick though from someone that actually used a 300 baud modem without dialing function, baud != bps [0]

[0] https://www.linuxjournal.com/files/linuxjournal.com/linuxjou...

The content can be performance metrics before and after the Ethernet card.

>Perhaps it's simply impractical on such modest hardware

I imagine it's not just the hardware limitations, but the available software. This one, for example being MS/DOS, where there were never really any serious server-side http/tcp implementations.

On the other hand, there were very busy BBS systems running on DOS where there had been time for years of various optimizations to happen.

It is probably the modem honestly. The 386 is well capable of saturating a 38.4k modem many times over.