Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

"I think you will all appreciate this person's commenting style"

jwz.livejournal.com

Post reply on HN
Print view View original

41–50 of 91 posts

Re: "I think you will all appreciate this person's commenting style"

#41

Post by taejo »

yason wrote: post #37
saurik wrote: post #2

PSD was never intended to be a data interchange format: it is the serialization format of a single program that has more individual unrelated features that actual people rely on than almost any other piece of software and has maintained striking amounts of backwards compatibility and almost unbroken forwards compatibility during its over two decades of existence. This product's "file format" needs to be critiqued in…

If a wise programmer decided he needs a serialization format, would he deliberately include in that format all the crap so vividly pointed to by the article? No. He will think of the "serialization format" as an interchange format between two different instances of his program. One process first writes the data file and another process later will read it. He also knows that sooner or later the "serialization format"…

Word dates back to 1983, while OLE was only introduced in 1990 (but otherwise I think you are correct)

Re: "I think you will all appreciate this person's commenting style"

#42

Post by Maakuth »

yason wrote: post #37
saurik wrote: post #2

PSD was never intended to be a data interchange format: it is the serialization format of a single program that has more individual unrelated features that actual people rely on than almost any other piece of software and has maintained striking amounts of backwards compatibility and almost unbroken forwards compatibility during its over two decades of existence. This product's "file format" needs to be critiqued in…

If a wise programmer decided he needs a serialization format, would he deliberately include in that format all the crap so vividly pointed to by the article? No. He will think of the "serialization format" as an interchange format between two different instances of his program. One process first writes the data file and another process later will read it. He also knows that sooner or later the "serialization format"…

It could be possible that the format was first very reasonable, but the surrounding platform has changed completely during the development. Then the new layers of specification have been added in a form that seemed to be the best possible solution on that platform and on that time. Wasn't Photoshop at the beginning an app for the original m68k Macintosh? Surely different kind of field sizes made more sense in that world than ours - also the tradeoffs in the sake of performance could have had some say.

Re: "I think you will all appreciate this person's commenting style"

#43

Post by Camillo »

saurik wrote: post #2

PSD was never intended to be a data interchange format: it is the serialization format of a single program that has more individual unrelated features that actual people rely on than almost any other piece of software and has maintained striking amounts of backwards compatibility and almost unbroken forwards compatibility during its over two decades of existence. This product's "file format" needs to be critiqued in…

> I am thereby having a difficult time fathoming why anyone would think that a PSD file is thereby going to be some well-organized file format that they should easily be able to parse from their own application is just naively wishful thinking

I like how you embodied your point in the unsyntax of that very sentence. ;)

Re: "I think you will all appreciate this person's commenting style"

#44

Post by SideburnsOfDoom »

saurik wrote: post #2

PSD was never intended to be a data interchange format: it is the serialization format of a single program that has more individual unrelated features that actual people rely on than almost any other piece of software and has maintained striking amounts of backwards compatibility and almost unbroken forwards compatibility during its over two decades of existence. This product's "file format" needs to be critiqued in…

> PSD was never intended to be a data interchange format

And that's the basic design flaw - it is a data interchange format despite not being designed as one, and the terrible job that it apparently does at it. The people who wrote it didn't recognise that they were going to be filling that need. There's a lesson in there somewhere.

Re: "I think you will all appreciate this person's commenting style"

#45

Post by lifeisstillgood »

yason wrote: post #37
saurik wrote: post #2

PSD was never intended to be a data interchange format: it is the serialization format of a single program that has more individual unrelated features that actual people rely on than almost any other piece of software and has maintained striking amounts of backwards compatibility and almost unbroken forwards compatibility during its over two decades of existence. This product's "file format" needs to be critiqued in…

If a wise programmer decided he needs a serialization format, would he deliberately include in that format all the crap so vividly pointed to by the article? No. He will think of the "serialization format" as an interchange format between two different instances of his program. One process first writes the data file and another process later will read it. He also knows that sooner or later the "serialization format"…

The overriding aim of most formats was to load into memeory efficiently - fast load times was the key winner in the 80s and 90s. So you did not want a simple serialisation because that meant slow CPU intensive save and loads. But if you slammed it in pretty much as it would be in memeory you would win. Downside is if you change the in memeory representation of the running program you had to change the file format.

And .mov would have no such concerns - it's prime use case is store data in serialised chunks anyway - it was already serialised so could use very dumb stores.

Re: "I think you will all appreciate this person's commenting style"

#46

Post by TeMPOraL »

SideburnsOfDoom wrote: post #44
saurik wrote: post #2

PSD was never intended to be a data interchange format: it is the serialization format of a single program that has more individual unrelated features that actual people rely on than almost any other piece of software and has maintained striking amounts of backwards compatibility and almost unbroken forwards compatibility during its over two decades of existence. This product's "file format" needs to be critiqued in…

> PSD was never intended to be a data interchange format And that's the basic design flaw - it is a data interchange format despite not being designed as one, and the terrible job that it apparently does at it. The people who wrote it didn't recognise that they were going to be filling that need. There's a lesson in there somewhere.

> There's a lessen in there somewhere.

Greetings. I have arrived from the future to spare mankind more years of pain by stating it clear here that the lesson is not "serialize your data to XML".

Re: "I think you will all appreciate this person's commenting style"

#47

Post by beagle3 »

greggman wrote: post #36

I'm pretty sure the PSD format chucks are based off IFF spec from 1985 http://www.martinreddy.net/gfx/2d/IFF.txt Things were padded to 4 byte boundries because the 68000 processor would crash if you read an unaligned 32bit value. So the length of the actual data was what you find in the size field of each chuck but each chunk is padded. That way you didn't have to work around the 68000 quirks and read a byte at a tim…

> Things were padded to 4 byte boundries because the 68000 processor would crash if you read an unaligned 32bit value.

It is actually padded to 2-byte boundaries. The 68000 had an external 16 bit data interface. That's the only thing I would fix about IFF if I redid it today. (And I would add a 64-bit length extension, and a "reserved chunkid" designation, e.g. anything that starts with a '$' must be registered in some central registry)

Re: "I think you will all appreciate this person's commenting style"

#48

Post by ibotty »

saurik wrote: post #2

PSD was never intended to be a data interchange format: it is the serialization format of a single program that has more individual unrelated features that actual people rely on than almost any other piece of software and has maintained striking amounts of backwards compatibility and almost unbroken forwards compatibility during its over two decades of existence. This product's "file format" needs to be critiqued in…

i'm not sure i get your point about the similarity to (early) office data formats. these are very badly supported now. that's a stark contrast to your assertion that psd is backwards and forwards compatible to a very large degree.

care to elaborate?

Re: "I think you will all appreciate this person's commenting style"

#50

Post by SideburnsOfDoom »

yason wrote: post #37
saurik wrote: post #2

PSD was never intended to be a data interchange format: it is the serialization format of a single program that has more individual unrelated features that actual people rely on than almost any other piece of software and has maintained striking amounts of backwards compatibility and almost unbroken forwards compatibility during its over two decades of existence. This product's "file format" needs to be critiqued in…

If a wise programmer decided he needs a serialization format, would he deliberately include in that format all the crap so vividly pointed to by the article? No. He will think of the "serialization format" as an interchange format between two different instances of his program. One process first writes the data file and another process later will read it. He also knows that sooner or later the "serialization format"…

> AFAIK, the Word .doc also started (and unfortunately continued) as basically a not-so-designed memory dump

This may be true but not the whole story. It's the reason why the MS office team bit the bullet and replaced .doc with .docx about 5 years ago http://en.wikipedia.org/wiki/Office_Open_XML

Docx is basically XML in a zip file. It's a beast and has lots of compromises for backward compatibility, but as a design starting point, "zipped XML" is far far better than a binary dump of the in-memory data.

Post reply on HN