Bootable and non-Bootable

I've had a MacBook Pro for 5 years and haven't backed up a bit, a nibble, a byte - anything, and I've dropped it onto hard ground (switched off) twice such that the casing has been dented at corners. That was over two years ago and the machine hasn't missed a heartbeat, so I've seemingly got an indestructible machine with a solidly constructed hard drive. However, for no particular reason, I'm now looking into wasting a bit of time in, perhaps, doing something I've never done - backing up. (This is my first machine.)
Now, I know of Time Machine, and by reading some of the forum threads I gather it only backs up non-OS data, and that may not be good enough if you need to restore your system to a state exactly as it was before the presumed disaster. To do that you must make an exact copy of the hdd (clone) by using software such as SuperDuper or CarbonCopyCloner, and an advantage of using such a cloner is that such copies are bootable, by which term I presume is meant that, in some way, you tell your stricken machine that the installed hdd is to be bypassed and instead look to the cloned copy for the software and data to bring the OS to life. By the way, I have seen it pointed out that Time Machine does not produce bootable copies, but that is obviously because it does not even back up any of the OS anyway.
But even if you could choose the OS files to be backed up by Time Machine, possibly by making them unhidden, I suspect that such a backup would not be bootable since, I think (and this is the essential difference between a bootable and non-bootable copy), a bootable copy has to have certain basic system data in certain initial storage areas of the backing up media - e.g. sector 0 of track 0 of disc 0 if it were an hdd - and since Time Machine has been designed to only copy non-OS data (notwithstanding my earlier conjecture about possibly choosing unhidden system files) then the designers would not have to put any data anywhere in particular on the backup medium, so would not be able to produce a bootable target.
Speak out if anything I've said here is wrong or if you can comment or embellish further. There are some implicit questions that I've posed, for example about how to get the machine to look elsewhere for the bootable system, so I hope someone with that knowledge can answer that question.
By the way, if it matters, my OS is Mavericks, v10.9.4.

Your "understanding" of Time Machine is a bit off.... Time Machine will backup everything including system files, kexts, etc. However, it does not make a copy of the EFI partition which is required for booting the machine. Carbon Copy Cloner and SuperDuper are cloning applications. It should be noted that the only true cloning application is Carbon Copy Cloner since it will clone everything including the recovery partition. SuperDuper will not.

First off a few corrections about Time Machine:

1. Time Machine will copy OS/System files unless you specifically exclude them. If the file is on a Mac formatted drive Time Machine will copy it. If you are running Windows in a virtual machine program such as Fusion it will even copy that. IT does not copy Bootcamped Windows installations.

2. Even though Time Machine copies the system files the Time Machine copy is not directly "bootable". You have to either reinstall the OS first or boot from the recover partition and reload files from the Time Machine backup.

3. A bootable "clone" of the system can be used to restore the system to whatever condition it was in at the time the clone was made. These are generally kept on an external hard drive. You can boot from them by holding down the option key right after startup and choosing the external drive from the list of boot drives that appear.

Hopefully that clears things up. post back with any follow up questions.

I for one prefer SuperDuper, after downloading the operating system Mavericks and making a bootable USB thumb drive prior to running the Installer. SD does a 'smart backup' to the external drive when you choose, say once a week, and reads the internal drive and copies any changes to the external.

The cloned backup is bootable.

I use CCC the same way harryb2448 uses SD, except I do an automated daily backup just after midnight local time. The cloned backup is bootable. I also use TM to do a twice a day backup to a different external drive. Yes, I'm paranoid, but then again, I've had two drives fail at the same time and actually lost data, so making two separate backups makes sense for me. If I have a three-drive failure I'll get a third backup system going...

I've been participating in a discussion on this very topic in another forum. Here's the bottom line: both Time Machine and cloning have distinct advantages, and using both is probably the best route for local backups.

Time Machine is great for retrieving accidentally-deleted files or earlier versions, since that's what it does -- incremental backups. It's also fantastic for restoring a complete system. It's normal schedule of updating every hour ensures little to no data loss, even if the user does something stupid, but also great for -- as the name implies -- going back in time to rescue older data.

Clone programs like SuperDuper or CarbonCopyCloner or ChronoSync -- of which cost about $40 -- are great for troubleshooting, for quickly getting back up and running in case of a boot failure, and also for restoring a system. Of course, most people only do clones periodically, since they take more time, and thus in the case of a catastrophe you will only get back up to the point of the last clone.

Obviously solution: use both! That's what I've done for years now -- I have in effect two backups: a Time Machine drive that's updated hourly as normal, and a clone I have set to update itself every week. The whole system is automated so other than mount the clone drive there's nothing much for me to do.

I'm really looking forward to iCloud Drive (coming this fall), as it looks so far like it's going to be an idea and affordable option for off-site storage of my photos in original format and resolution, and also as an encrypted off-site solution for the much smaller amount of data I need to back up off-site that would be really hard to replace (financial records, legal documents, that sort of thing).

Thank you all for replying to my post - I hope this further missive will receive as much attention.
I am receiving the Mac-Forums newsletter and it is the one sent to me on 11th July with the reference to 'Can't copy files to backup ext drive' that led me to the (mis)understanding of Time Machine and the other software mentioned there. Referring to that posting, moderator member chscag gave the explanation for the problem reported as that the drive being copied to from a Mac was probably formatted NTFS not (as moderator member slydude later mentioned) Mac OS Extended Journaled. That seemed to be the solution though the reporter had other problems. So, getting back to Time Machine, SuperDuper, CCC, et al, I presume that these all have a target drive formatted Mac OS Extended Journaled? Either it is pre-formatted or the software may be able to detect and correct any drive formatting needed. Switching now to this thread, a reply by senior member chas_m says that he's looking forward to iCloud drive to store photos, text, etc. Now, is it right that this iCloud drive would be formatted Mac OS Extended Journaled, presuming the iCloud he's referring to is Apple's? If that is the case then what is the formatting when you copy to Google Drive or Microsoft's OneDrive or any other online storage? And what is the formatting when you copy stuff from a Mac and Windows to, for example, Google drive, presuming that can be done.
Can online storage be used as the target for Time Machine or the cloners? (By the way, chas_m is looking forward to (the availability of) iCloud Drive but don't we already have it? When I go to iCloud in System Preferences it says I have 5gb, and I can buy more - is this storage different to the mentioned iCloud Drive?)
Going onto a tangent, in chas_m's reply he has a link to his 'Sage advice for the new Mac switcher', and he mentioned the following on 14th July 2010: 'As it happens, keeping a ton of stuff on your desktop will slow down your machine ...' - it happens that I do have stuff on my desktop, but why would it slow down my machine? (For it to be mentioned the slow down must be somewhat significant.)
Lastly, EFI? I have a sense of this from Wikipedia as being equivalent to the BIOS but otherwise I've never heard of EFI or UEFI. But what is it about this EFI that Time Machine won't or can't copy it? Is it a matter of being a separate partition? Even so, why doesn't Time Machine go all the way and produce a bootable copy - why doesn't Apple provide the equivalent to a cloner?

First let's deal with formatting and clone drives. Most users format the drive to Mac OS extended journaled before starting the clone. If I remember correctly most cloning program will however ofter to format the drive if it is not already in the right format.

When copying files to an online service such as iCloud, OneDrive etc. as far as I know the formatting of the drive in question is not really relevant in most situations. The Extended journaled vs. FAT 32 vs. NTFS issue really only comes into play when the drive is directly connected to the Mac.

Apple didn't really clarify everything about iCloud Drive at the recent developer conference. As it stands right now the space that available functions mire like online storage. The new incarnation of the service seems to be aimed at competing with services such as Drop Box. See Apple Unveils iCloud Drive Storage Service, Alongside iCloud Photo Library | NDTV Gadgets

As far as the number of files on the Desktop these days you may get varying answers about that. In the early days of Macs keeping too many files on the desktop really caused problems. The Desktop is essentially a folder and at that time there was a limit to how many individual items that could be in each folder. On older systems, having to draw a lot of icons on the desktop (one for each folder or document) could really slow the system down.

As for why TM does not make a bootable copy, that's simply not how it works. It just does backups. The backups CAN exclude system files if you choose to do so, so the backup is just that, a backup you can configure. It's good for restoring lost files or after hardware replacement. Because TM was ONLY a backup, developers of Carbon Copy Cloner and SuperDuper! decided to create a different service, this one a cloning service to allow you to both backup AND boot. But by default those services don't do what TM does, which is to make an automatic backup on a schedule. Yes, you can set up CCC and SD! to do timed backups, but TM was automatic and default. All you have to do with TM is turn it on and you have an time-related archive at your fingertips. CCC and SD! clone and boot, but getting archives and timed backups require some configuration. There is no "why," that's just how it is.