Memory leaks detection paper co-authored by Netflix CEO Reed Hastings in 1992 [pdf]

https://web.stanford.edu/class/cs343/resources/purify.pdf

by mfiguiere • 4 years ago

203 63 4 years ago

web.stanford.edu

andsoitis• 4 years ago

Hastings co-founded Pure Software in 1991. Their products were for software troubleshooting.

He co-founded Netflix in 1997.

https://en.wikipedia.org/wiki/Reed_Hastings

fnordpiglet2• 4 years ago

Pure products were amazing. I always found the way Quantify represented profiling to be incredibly helpful back in the ancient days. I know there’s more advanced visualizations but I always found the logarithmically scaled directed edges in quantify to speak to me better than flame charts and other related techniques, I think because it represented the full execution graph rather than individual transactional paths. Anyway huge respect for Reed as an engineer and have always been impressed with both Netflix and the quality of the performance, debugging, and other efforts that have come out from them. He clearly values excellent engineering.

iot_devs2• 4 years ago

Do you have a picture of these "logarithmically scaled directed edges"?

I can imagine what you mean but a visual aid would be super useful.

ww520• 4 years ago

No wonder Netflix has such a huge emphasis on engineering talent.

gardenhedge4• 4 years ago

But Netflix was originally DVD rental. At that time it wasn't a tech company was it?

mark_l_watson2• 4 years ago

Pure was an amazing product. For C++ development, we relied on it for my team at SAIC, and when I moved to Angel Studios (we developed games and content for Nintendo, Sega, Disney) I immediately asked the owners to purchase a company license.

I saw Reed Hastings being interviewed on YouTube last night - fascinating how he has so many personal friendships with CEOs of competing companies.

hodgesrm• 4 years ago

Purify could find memory errors in just a few minutes that would take engineers days or weeks to track down. The dynamic instrumentation capability on existing binaries was huge. The first time I saw it in use was at Sybase. Running a demo version for an hour found enough problems that we instantly sprang for the license.

timeimp• 4 years ago

Angel Studios

Was this the company that made Midtown Madness 2?

neilv3• 4 years ago

Purify was awesome back then, before Linux and the open source tools.

(I think Purify might've been the first phoning-home tool I saw, finding a way to email Pure if you exceeded your simultaneous licenses, but I might've misunderstood at the time. Around that time, it was normal for big-ticket Unix workstation software to have network license managers, which were tied with stale NFS mounts at our site as the most common cause of a fleet of expensive engineers on expensive workstations with expensive software all suddenly unable to work. :) )

A related awesome C development tool we used for discovering memory errors before then was the Saber-C debugger. https://www.softwarepreservation.org/projects/interactive_c/...

SanjeevSharma• 4 years ago

I worked at Rational Software when we acquired Pure software. We sold tons of Purify+. The legend of course was the Hastings took the $ he made from selling Purify to Rational to start Netflix. So as a Rational employee, I had a contribution to Netflix's existence... Or so I like to tell myself ;).

ivanech• 4 years ago

I have a copy of the Pure Software Engineering Handbook which was created for internal use only. It's amazingly comprehensive and well-organized. I've never seen any kind of onboarding that comes close.

geophile• 4 years ago

Purify was a fantastic tool. I was so surprised to find out that he went on to found Netflix.

bitexploder• 4 years ago

I remember using that and libefence in the 90s to find memory leaks in my MUD. Purify was better. Easier to use and found more stuff. It is 2022, leaking memory still a problem.

curiousDog• 4 years ago

Having met him before, his clarity of thought just comes across in this paper as well. Some people are just wired with that talent that makes me so jealous. Reed is one of those people with high EQ and IQ (with the ability of handle his inner Elon diplomatically)

hackernewds• 4 years ago

Curious what "inner Elon" implies

bantunes• 4 years ago

The little voice that says something is only worth doing if it boosts your ego somehow.

jdp23• 4 years ago

Back in the day Reed told me that he added the leak detection to Purify v1 towards the end of the dev cycle and was very surprised that it wound up being one of their biggest selling points

ryanmccullagh• 4 years ago

what's the difference between this and valgrind?

projektfu2• 4 years ago

A major difference is that purify is a binary transformation performed before or after linking. Valgrind/memcheck is a virtual machine that jit-compiles executable code and adds its instrumentation in the process. So, with purify, your linked executable includes the checks. With valgrind, the unmodified executable can run with or without checks.

GuB-42• 4 years ago

And for a more practical comparison: https://valgrind.org/gallery/survey_03/q4.html

The takeout is: valgrind is free and doesn't require recompilation, purify has a more complete UI, they both have similar performance impact and bug-finding abilities.

wallstprog2• 4 years ago

I used Purify back in the day, and while it worked well, getting it working was a royal PITA. IIRC it was necessary to recompile EVERYTHING with Purify.

Anyway, I would think the gold standard these days is clang's Address Sanitizer (https://github.com/google/sanitizers/wiki/AddressSanitizer). clang/ASAN also runs on Mac in addition to Linux.

kccqzy• 4 years ago

Having never used Purify back in the day, I really wonder, do you think address sanitizer is an adequate or better replacement for Purify?

jll29• 4 years ago

I hadn't realized Pure and Netflix had the same founder; Purify was an amazing tool, which we had a license for HP-UX at uni. It was the kind of software where you knew you'd ask for it to be bought by any future employer.

rajnathani• 4 years ago

Recently I was thinking about how the Netflix software strategy of hiring only experienced engineers [0] (and paying them really well), is pretty beneficial for almost any tech team/company.

Things like the CS experience that Reed Hastings has, seems like the key driver here.

[0] https://www.teamblind.com/post/Why-Netflix-only-hires-senior...

Memory leaks detection paper co-authored by Netflix CEO Reed Hastings in 1992 [pdf]

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