Prior to 1995, CD-ROMs could not be used for booting a computer. The CD drives required software drivers to be loaded first from a floppy or hard drive with an operating system. In early 1995, the manufacturers of PCs, CD-ROM drives and discs, and the software industry finalized the El Torito standard.

The El Torito standard required three parts to function.

A CD-ROM drive with a boot mechanism, normally using IDE or EIDE type interfaces.

A motherboard that had a new BIOS that supported the CD-ROM directly.

A CD-ROM disc with boot code and an operating system.

The El Torito standard is commonly used to install an operating system onto a new computer or one with a reformatted hard drive. Customized install discs can also be made, where corporations can set up a standard PC for their employees just by popping in a bootable CD disc.

Update: As Gorgonzola noted, there was/is an americanized Mexican restaurant called El Toritos. Unfortunately, the history of the name of the standard is not as well documented as the High Sierra one is, but it is generally suspected and assumed that the original group of the standards development folks met at the mutually equidistant and easy to find restaurant.

I personally was curious as to where the name of this standard came from. The standard document, at the Phoenix technologies website, didn't mention the history of the name.

This allows me to push any old theory that strikes my fancy¹.

You might think that over here on the East Coast, I am at a disadvantage for ferreting out little tidbits of knowledge like this.

But no, I've been to California a few times, and I know that there's a very prominent chain of restaurants serving Pseudo-Mexican food² called El Torito.

So I can imagine a couple of guys popping in to a San Jose El Torito in late 1994 and writing the initial version of the standard down on a leftover flour tortilla. OK, so maybe they brought their notebook computers with them.

Still, It would certainly explain the refried beans that got dripped on my System CD.

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¹As I am fond of saying, I never let the facts get in the way of a good story.
²Still better than East Coast "Mexican" food.

If there's one thing you need to know about the El Torito spec (PDF file available at Phoenix Technologies website) it is this: ALL and I mean ALL numbers are in hexadecimal unless specifically noted otherwise. This even applies when when the spec refers to quantities. When the spec, such as it is, refers to a quantity of bytes, say "200 bytes", it really means 0x200 bytes (512 bytes decimal). Even though the spec tells you that all numbers are hex, it's extremely easy to forget that when it talks about "200 bytes" that it really means 512 bytes. (I know this via the hard way.)

I've also heard the Mexican restaurant story. Don't know if it's truth or legend though.

Also, I booted plenty of Sun's Sparc machines prior to 1995 from CD-ROMs. You just couldn't boot most Intel boxes from CDs prior to 1995. Compaq's machines could boot from SCSI CD-ROM drives in a proprietary manner prior to 1995 as well.