That doesn't give a reliable answer as the installed game is not compressed data, like the original installation data on the floppy disks probably was. Also the floppy disks may have included stuff that doesn't necessarily get installed, at least if it is optional.

I'm pretty sure that many of the games I'm interested in checking are old enough that compression wasn't really feasible, due to CPU and RAM requirements. For compression to be useful, you need to have enough RAM or hard disk space to store the uncompressed data, and older games were made for systems that typically had less RAM than the size of a floppy, and no hard drive.

Also, it appears the .ZIP file format didn't actually appear until 1989, so older games would have had to use something else, if they were going to use compression.
I am actually thinking of games that old here.

Interestingly, on Linux, if the file system overhead is preventing you from fitting a file on a disk, you can just copy (or dd) the file to the device node, which will put that file on the disk without any filesystem overhead. A simple copy (or dd) can be used to retrieve the file on another machine.

Using this, for example, with tar, will allow you to fit multiple files with significantly less file system overhead. The catch is that you lose random access, and you also lose the ability to easily modify the file system.

You can see the size of the game offline installers on gogdb, for example here:

https://www.gogdb.org/product/1207658924#downloads

The executable usually is a few MB in size, the rest is divided in 4GB packs.



edit:
The number of discs of the original verion actually varies depending on where you buy from.
While in Europe Kotor or DoW were released on 1 DVD each, the US version was released on several CDs.

And then there are games like Tex Murphy Overseer (or X-Files, but that's not on GOG) of course which first got a CD release and then a DVD rerelease. Jungle Strike? First floppy Disk, then CD version with enhanced video (Loom got a CD version with CD music and speech, Indy 4 got a talkie version on CD, also Monkey Island 1 and 2 were rereleased on CD).


I used to create install DVDs from my CDs, if that was possible. In some cases the installer had to be edited to recognize the disc name.

Black Dahlia on 8. O.o

Fun fact: Remember all the colored lines on the screen when loading Amiga games? (on copied games mostly, since those had more data than the original)
That was the game loader using the video memory to decompress the data from the disc.

The first digital compression algorithms appeared in the 50s already, but only in the late 70s they became a thing really.
They really took of in the late 80s however with PKZIP. Then others saw that there was money to be made and the fight began.

People also tend to confuse GB and GiB (so does Microsoft). 1 GiB = 1.099 GB
Windows displays GiB, but labels them GB.

DVDs come in different sizes. 4.7GB (4.35GiB) is a common standard. This is the format the GOG files (3.99GiB = 4.3GB) are targeted for.
In order to put them on a ~3.99GB(4.37GB) DVD, you need to "overburn" the DVD by 327 MB, which is often very likely to fail. Also on disc 1 you need to add the installer which adds another ~2 MB.
So either use 4.7GB DVDs or 9.4 for adding 2 files on each, the 8.5GB DVDs are not big enough for 2 files.

The first Monkey Island had 4 disks on Amiga, Monkey Island had 9, Indiana Jones 4 had 11 disks, where the Amiga uses 880KB discs.
The EGA version on PC takes 2.7MB, so it was probably shipped on 2 disks (assuming it was shipped on 1.44 3.5" disks, but given the time it could have been 4 x 720KB disks). The VGA version takes 3x 1.44MB disks.

The joke was about disk 22. It was removed in later versions since people kept calling the Lucasfilm hotline about missing disks.

Turrian 2 (Amiga) can be downloaded from the developers site for backup reasons, however it has a file size of over 3 MB, where the original game was shipped on only one disk. That's some badass compression.

Compression would still be feasible, but it would be very simple things, RLE, and buffers may be as small as 4k. Though likely bitpacking or whatnot. Some games (Elite) data was made on the fly using a type of generation rather than actually storing anything at all.

Though if you're talking about when they literally HAD 8k or less in RAM, then yes compression wouldn't be feasible. Smaller than that size and ROM data via chips may have been more likely than using disks.

Yes, but almost all games were likely MS-DOS, less likely to be Linux/Unix systems. Linux kernel didn't exist before 92 when Linus put it on a bulletin board/email he was writing one. That and Unix systems weren't really popular until much later (not to say there's no games at all for Unix/Linux).

Personally with how usable and modular Linux is today compressing a directory into squashfs and then dding that onto a floppy and mounting it would certainly work, keep random access, but is read-only like a compressed CD-ROM. Though SquashFS started coming into existence in 2000.

Back when I was a child I had an old apple 2e, that like you said didn't have a HDD, the IBM compatible 286 my parents had was built with a 40 MB HDD. I was allowed to use a 20 MB partition on it for games and my own use. Many games had multiple install options. Some could run from the disks, some would install data for the entire game, some would install base data and then use a disk as a play disk. I remember many of my Sierra games came compressed and needed to be installed first. As a side note, I remember using the .lha compression format quite a bit back in the 5.25 and 3.5 floppy days. A quick google search reveals it was created back in 1988

Worth noting that compression is less of an advantage when the data is stored on a cartridge. Thing is, one advantage of cartridges, which is particularly important when talking about low RAM systems like the NES, is that the cartridge's contents map directly into the CPU's address space (and sometimes the graphics hardware's address space as well). Hence, one does not need to copy cartridge ROM into RAM before it can be used. However, if you're decompressing it, then the uncompressed data must be stored somewhere, and that somewhere can't be the same ROM used to store the compressed data. In other words, you can't free the compressed data in ROM.

Compression on disks makes more sense. The data has to be loaded into RAM anyway, and once the data has been decompressed, the RAM used for the compressed data can then be freed.

(This is why cartridge based systems can work with so little RAM, and why the Famicom Disk System has extra RAM, to account for the fact that the data can't be used without first copying it to RAM, something unnecessary with cartridges.)

No clue about the original side-scrollers, but if we're speaking of Duke Nukem 3D, that was only released on CD-ROM (1 disc, at least for the original full-version release; not sure whether later editions which included expansions might've added another disc).

Atomic Edition was on one CD as well.

Mhmm... I was meaning more in the loading data from disk per sector, but that would be more background OS function. Also in say something you could heavily compress like a text adventure it might be useful, even if it's just repacking to drop 2 bits per byte per character to get marginal gains for what would be displayed for only a minute at a time.

One game that did use compression in the ROM was Super Mario Brothers. The level compression scheme more or less being length and type combo, 256x8 or 2k block per level (which i think the first level is stored in like 100 bytes while otherwise it would be much larger). But when you have 40k of ROM data to work with...

LHA, there was also APE ARC and a few other oddities i think.

Well i'll watch Computer Chronicles, and see if i find anything interesting.

edit: A blast from the past. though everything they talk about certainly seems like stuff we don't worry about right now. they don't cover much outside of basically what became the standard in that time.

That's right! This game was so impressive for me back in the day that I bought I copy even before having a computer that could run it. Later on I also bought Phantasmagoria 2: A Puzzle of Flesh, which came on 5 CDs.

X-Files the game had 7 CDs as well. The later released DVD version had improved MPEG2 video. Back then it was the biggest problem to get the MPEG2 video to work (many people only saw a black screen). These days the problem is the game engine. One can still run the game using a Quicktime Emulator.

Oof. Interesting data to know. B ut I don't know it out there. Also gets muddied. My physical copy of Drakken came with 3 disks, but they were just CGA, EGA, and VGA versions of the game. Not like Lands of Lore that had multiple floppy diskettes and then a giant post-install prerender process.

Back then, it also varied widely. things weren't standardized. I know other people around the same time only had 1 disk in their Drakkehn, the VGA version. Games lingered on shelves more, different distribution channels. Even 5.25 vs 3.5 floppy versions for the same game (for a while, both at the same time in the same box!).

File size, removing the GOG customizations, might be a better measure. But that's also a problem... since games had to duplicate some data on the disks. (Famously, Phantasmagoria's 7 disks were all mostly identical except a few chapter-specific movies.)