I used to be a graphics card/chip architect for macs in the early/mid 90s - our chips were the fastest, but some programs were resistant because they did stupid stuff: pagemaker invalidated the font cache every time it went thru its main loop, quark with ATM did an n*2 thing every time it wrote text etc etc. We had special hardware to accelerate text drawing and it did nothing because the software pissed it away. We considered creating a plugin that fixed all these things, it would have been hard to maintain, in the end we travelled around to the people who made these apps and talked them through their problems

To be fair excel would erase places white that it wanted to write up to 9 times before it drew any black pixels, we made that very fast! we didn't tell them :-)

At the time 24-bit framebuffers were so slow that before we built graphics acceleration hardware people would switch back to 8-bit to get stuff done, making 24-bit/true colour your daily driver was a big step forward.

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nxobject 2 hours ago | parent | next [-]

Does that make you the first in a long tradition of GPU developers going to blockbuster app devs to say "hey, you should be doing this instead?"

PS – I am looking through the NuBus cards that I have... did you work for SuperMac or RasterOps?

	▲	Taniwha 43 minutes ago \| parent [-]
		I was probably not the first to have to do that, we knew what apps our customers used, making them better was the whole point of the operation I did the architectural design for the SuperMac cards. I figured out what needed to be accelerated, dropping code into people's machines to see where the cycles were going. Others did the physical design for the first 2 cards, I did the design of the chip in the Thunder and later cards (designed the data paths and state machines and a full simulation, someone else actually laid the gates) If your card has a SQD01 on it it's my work. It peaks at 1.5Gb/s on solid fills

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xattt an hour ago | parent | prev | next [-]

What would have been the purpose of stupid code like that?

Was it a workaround for things that didn’t fully complete on one iteration, so the devs kept hammering away at it until it worked?

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phire 38 minutes ago | parent [-]

They were most likely just bugs. Quite possibly really stupid bugs.

Not every bug results in the program doing the wrong thing, they often just make the program do the right thing very slowly.

And nobody notices, since it still produces the right result.

	▲	Taniwha 36 minutes ago \| parent [-]
		Yes, they were bugs, I think programmers (and their marketing people) were more focused on new features than performance

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urbandw311er 4 hours ago | parent | prev | next [-]

This is a horrible and yet not unexpected insight into the internals of Excel

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Taniwha 4 hours ago | parent | next [-]

To be fair this was Excell 25 years ago, may no longer be true.

One of the other bugs (the Quark/ATM one) was also because of the programmers were worried about writing over stuff that hadn't been completely erased, the Quark guys wrote a string with 2 spaces at the end through a box that masked the end of the string, the ATM font renderer saw it couldn't fit the text so it split it in half and tried again so it drew N/2 N/4 N/8 ... strings. It spent all it's time in the 68k's multiply instructions figuring out how wide the strings (and substrings) were, our fancy 24-bit character rendering hardware was an afterthought

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bathtub365 4 hours ago | parent | prev | next [-]

In all of the software you’ve written, are you aware of how many on-screen pixels you’ve overdrawn?

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trelbutate 3 hours ago | parent | prev [-]

> To be fair excel would erase places white that it wanted to write up to 9 times before it drew any black pixels

I feel like I'm having a stroke trying to read this, what does it mean??

	▲	Taniwha 39 minutes ago \| parent \| next [-]
		Well all they needed to do was erase the screen with white and draw on it, but their app's internal logic meant that they erased it more than once. I was capturing QuickDraw library calls - the low level graphics primitives, to figure out where the graphics time in apps was going and found out sometimes excel did it 9 times Of course users didn't see it more than once, but our hardware made all that wasted time run faster
	▲	NSUserDefaults 3 hours ago \| parent \| prev \| next [-]
		Several layers of white is what makes the black really pop. (Just kidding).
	▲	b112 3 hours ago \| parent \| prev \| next [-]
		It means they were time travellers! Secretly, they came from an alternate future where everyone used e-ink displays, and wanted Excel to be ready!
	▲	sixeyes 3 hours ago \| parent \| prev [-]
		before writing to some area, it would erase it (clearing with white) up to 9 times

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PaulHoule an hour ago | parent | prev [-]

I remember when 24 bit color was exotic and aspirational and you had to settle for 16.