Hacker News: steerablesafe

New comment by steerablesafe in "Tell HN: Adobe took down the PDF 1.7 specification from their site"

steerablesafe — Thu, 31 Mar 2022 14:02:58 +0000

The specification does have a hierarchical outline, and you can click on cross references too. Of course navigation can still be cumbersome, linking to chapters can also be awkward (tip: right click on outline element and copy link works in Firefox).

There are some problems of the spec though, and navigation is not the most pressing one. The spec is huge, support for less used parts is spotty in various PDF readers. It also has inaccuracies (not corrected in errata) and underspecified parts.

New comment by steerablesafe in "Tell HN: Adobe took down the PDF 1.7 specification from their site"

steerablesafe — Thu, 31 Mar 2022 13:58:25 +0000

No worries! How did you find the "opensource.adobe.com" link? I can't hit it with google, even with aggressive searches like "site:opensource.adobe.com filetype:pdf". And I can't seem to navigate there from the main page.

New comment by steerablesafe in "Tell HN: Adobe took down the PDF 1.7 specification from their site"

steerablesafe — Thu, 31 Mar 2022 13:51:25 +0000

Ah, thanks for the link. For some reason that link doesn't turn up in google search for me, however hard I try. Of course the ISO one is also authoritative, but not free.

Tell HN: Adobe took down the PDF 1.7 specification from their site

steerablesafe — Thu, 31 Mar 2022 10:43:11 +0000

I just discovered that Adobe took down the PDF 1.7 specification from their site. It's used to be hosted at [1] and I can't find a replacement. Of course this doesn't mean that the specification can't be acquired freely from elsewhere [2, 3], but it's unfortunate if the authoritative source is down. Hopefully it is a mistake though and it will be back up.

[1] http://www.adobe.com/content/dam/acom/en/devnet/pdf/pdfs/PDF32000_2008.pdf

[2] https://christianhaider.de/dokuwiki/lib/exe/fetch.php?media=pdf:pdf32000_2008.pdf

[3] https://web.archive.org/web/20220309040754if_/https://www.adobe.com/content/dam/acom/en/devnet/pdf/pdfs/PDF32000_2008.pdf

Comments URL: https://news.ycombinator.com/item?id=30865719

Points: 114

# Comments: 36

New comment by steerablesafe in "Difftastic: A diff that understands syntax"

steerablesafe — Wed, 30 Mar 2022 09:45:13 +0000

What would be also cool is a syntax aware custom merge driver for git, but that's probably even harder.

New comment by steerablesafe in "Down the mechanical keyboard rabbit hole"

steerablesafe — Fri, 18 Mar 2022 10:08:07 +0000

You can have the numpad on the left, but I rarely saw keyboards like that. I saw some odd "left-handed" rubber dome keyboards, but that's it. You can also have a distinct numpad and put it anywhere.

New comment by steerablesafe in "Xdm – Powerfull download accelerator and video downloader"

steerablesafe — Thu, 17 Mar 2022 16:14:39 +0000

Sometimes the bottleneck is on the server end, and often they throttle throughput per connection. Some download mangers allow you to download the same file through multiple connections and range request. Having said that I think it's a little bit rude to work around the intended throughput limitation.

New comment by steerablesafe in "Xdm – Powerfull download accelerator and video downloader"

steerablesafe — Thu, 17 Mar 2022 15:41:02 +0000

I recommend aria2 for a similar purpose. Just `apt install aria2`. I'm just a happy user.

New comment by steerablesafe in "Show HN: PDF API – Generate, convert, and modify PDF documents"

steerablesafe — Thu, 17 Mar 2022 11:09:32 +0000

From the pricing page, limits seem to be on number of documents, not number of pages. Is the number of pages per document also limited?

New comment by steerablesafe in "Make a Fair Coin from a Biased Coin (2018)"

steerablesafe — Wed, 16 Mar 2022 14:59:29 +0000

It feels like an awkward middle ground. Like this method has a limited entropy output for the first 2000 coin flips (first 1000 double-heads/double-tails/mixed entries), and then suddenly it adds back a ton of lost entropy.

An other commenter linked to some papers for asymptotically optimal entropy generation, I wonder if there is more of a streaming method there. It feels like there has to be, even maybe after a slow start. My naive intuition is that after 1000000 coin flips you have a good idea what p is, and then you can basically do arithmetic coding from there. Of course a theoretically correct method can't do exactly this, but it might asymptotically approach it.

New comment by steerablesafe in "Update Firmware of Samsung SSDs in Linux"

steerablesafe — Wed, 16 Mar 2022 13:06:49 +0000

> My mouse looked like Christmas tree until I installed some electron app on windows.

At least solaar exists for Logitech stuff. Too bad it's still not something Logitech provides, but the reverse engineering work of some volunteers.

https://pwr-solaar.github.io/Solaar/

New comment by steerablesafe in "Make a Fair Coin from a Biased Coin (2018)"

steerablesafe — Wed, 16 Mar 2022 12:51:31 +0000

My impression is that arithmetic coding is the inverse. You have N symbols with different known probabilities, and you turn it into a stream of 1/2 probability random bits.

edit: On second thought this is probably a bijection and you can call it "arithmetic coding" in either direction.

New comment by steerablesafe in "Make a Fair Coin from a Biased Coin (2018)"

steerablesafe — Wed, 16 Mar 2022 11:36:32 +0000

This method generates approximately

  log_2(sqrt(1/(2*pi*p*(1-p))) - 1000*log_2(p^p * (1-p)^(1-p))

bits of entropy from 1000 coin flips, where "p" is the probablity of flipping heads.

Neumann's method generates 1000/(p(1-p)) bits of entropy from 1000 coin flips. The theoretical maximum is

  -1000*log_2(p^p * (1-p)^(1-p))

but it requires knowing "p" exactly. This method is close to the theoretical maximum. I didn't plug in numbers, or analyise further, but it's far better than Neumann's method.

One obvious drawback is that you have to flip the coin a 1000 times to produce the first unbiased random bit, while Neumann's method starts producing bits much earlier.

New comment by steerablesafe in "Make a Fair Coin from a Biased Coin (2018)"

steerablesafe — Wed, 16 Mar 2022 11:27:15 +0000

Arithmetic coding.

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

New comment by steerablesafe in "When or If"

steerablesafe — Mon, 14 Mar 2022 17:17:40 +0000

As an outsider to web development, @when would be a weird choice. If CSS wants to enable 3rd party tooling to take some of the syntax space, then it should declare some parts of the syntax never to be taken by core CSS (if it's not already done this way). Then this syntax clash would never be a problem between a 3rd party tool like sass and CSS.

In this case I think it's on sass to introduce the awkward workaround on the syntax clash.

New comment by steerablesafe in "Broadening compiler checks for buffer overflows in _FORTIFY_SOURCE (2021)"

steerablesafe — Mon, 14 Mar 2022 16:41:39 +0000

> is it even legal to memcpy more than a T's worth of data into a T? (IMO you shouldn't be doing that, but I think it's legal in C, and not with my template trick.)

How can you know if it's a single `T` or an array of `T` objects? You can memcpy into an array of `T` through a `T*` with no limitation on the size. I don't see anything inherently wrong with that either.

New comment by steerablesafe in "To save C, we must save ABI"

steerablesafe — Mon, 14 Mar 2022 13:10:37 +0000

It's well defined in the system V ABI, isn't it? Compilers do follow that. Otherwise no layout is defined by the C and C++ standards, even outside of bitfields.

edit: It's under "Bit-Fields" in [1]. I'm not entirely happy with the wording, but it's there.

[1] https://raw.githubusercontent.com/wiki/hjl-tools/x86-psABI/x...

New comment by steerablesafe in "To save C, we must save ABI"

steerablesafe — Mon, 14 Mar 2022 09:08:46 +0000

Bitfields are standard, what are you talking about?

New comment by steerablesafe in "Convert curl commands to code in several languages"

steerablesafe — Fri, 11 Mar 2022 17:26:12 +0000

I expected C with libcurl on the list, but in a sense that might be the toughest to implement.

New comment by steerablesafe in "UK tells operators to shut down crypto ATMs or face action"

steerablesafe — Fri, 11 Mar 2022 17:06:45 +0000

From experience, opening a bank account in the UK takes a while. And for that time you need cash on hand, or a working foreign bank account/bank card.