Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!wuarchive!emory!hubcap!gatech!mcnc!ncsuvx!news From: kdarling@hobbes.ncsu.edu (Kevin Darling) Newsgroups: comp.sys.amiga Subject: Re: Is CDTV CD ROM drive compatible? Message-ID: <1990Dec12.071439.7492@ncsuvx.ncsu.edu> Date: 12 Dec 90 07:14:39 GMT References: <90344.151536IO00844@MAINE.BITNET> <90345.021910R38@psuvm.psu.edu> <1990Dec11.095100.26677@ncsuvx.ncsu.edu> <1990Dec11.160910.17300@cbnewse.att.com> Sender: news@ncsuvx.ncsu.edu (USENET News System) Distribution: na Organization: NCSU Computing Center Lines: 76 In <1990Dec11.160910.17300@cbnewse.att.com> cwpjr@cbnewse.att.com (clyde.w.jr.phillips) writes: | In article <1990Dec11.095100.26677@ncsuvx.ncsu.edu> | kdarling@hobbes.ncsu.edu (Kevin Darling) writes: |> > CDTV is compatible with CDROMs that are of the ISO-9660 standard |> > format. Look for that designation on the label. |> |> That ISO standard is for the directory layout only. Unfortunately there |> is no standard yet for the actual data contained in the files. |> |> In the meantime, you virtually always have to have the specific program |> (the data retrieval engine) ported to your machine, in order to be able |> to access the data. There are a few discs with available data specs, |> but they're the rare case indeed, it seems. Most cdrom makers keep |> their data encoding a secret. - kevin |> | The first statement "directory layout only" would lead me to beleive | the "data retreival engine" (Device Driver) that comes with the | ISO CDROM Drive I bought for my (whatever) system can read any ISO disk | and tell me the file names on the CDROM. - clyde Apologies, I've been reading the CDROM forum on CIS so much, I forgot that "data retrieval engine" is semi-jargon. What it basically means, is "the (machine-specific) program code used to access the data". In other words, it's not the SCSI driver, nor the ISO9660 file system manager. Those are indeed drive/disc independent. But the actual access program and data code/methods are not. For instance, an encyclopedia disc will have a program designed to use the highly encoded (for speed) index of all words... a geography disc data engine would know about how the map data was encoded, etc. | I guess that I'd expect the standards of the target platform | to be the standards for the data in the files on the CDROM. | Is this wrong headed? - clyde Umm. Essentially correct. The data (especially graphics) will be packed to best fit the (graphics) modes of the target platform. But I doubt that you'd find recognizable "standards", such as .GIF files and so on. A related comment tells the story: <94076@aerospace.AERO.ORG> huebner@aero.aero.org (Robert E. Huebner): | My impression of this is- its sort of like putting an MS-DOS disk in your | Amiga using MSH: Sure, you can see the filenames, but without additional | software you cannot view the GIFs or execute a program. | Please, correct me if I'm wrong. You're right. The best way to think of it is this way: would you go into a software store and buy an MSDOS disk for your Amiga, and expect to use the program/data off it? No. Sure, with enough information, tools, and time, you might be able to get *something* (usually un-encoded text)... but it wouldn't be worth the effort. Porting the original retrieval software is the best method, and that depends on the cdrom creators. More apologies, as this is longer than I wished. But to go further: you'll often see Mac cdrom owners complain about not being able to use IBM discs, and vice-versa. Unless the cdrom creator saw fit to compile multiple retrieval engines (programs) for each platform, the disc is almost always useless in the non-target machine. Obviously, each maker has his own methods, and MSDOS people with multiple discs must load the specific retrieval program for the one they're using, each time. I once launched a tirade at cdrom makers on CIS about the non-independent data, and while it brought up _one_ maker (nutrition information disc) who said he did make his data encoding available, and also the fact that some gov't disc formats are available, the majority just shrugged. This is simply one of those cases where each company is in competition over storing and retrieving data in the smallest/fastest way possible, and to them a cdrom is just another giant floppy. Standards for now, at least, are pretty far from their minds. best - kevin PS: Other comments welcome. I've been following CDROM for some time, in hopes of creating access on other machines (amiga/os9/etc), but I am mostly a well-read armchair expert on the subject ;-).