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5th May 2003

KEN ABOUT ......... THINGS THAT SPIN

Ken Ross

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petlibrary@bigfoot.com


 

DESKTOP CINEMA

An update to an earlier link for a source of VCD films - lala.co.uk have now moved to a new place on the Internet. (http://www.dvddvdvcd.co.uk). Being CD they can be watched on your PPC Mac without having to upgrade - hurrah! Who needs a G3!

Doctor Evil's little clone II.

I'm all in favour of Linux (cynics may say that's because it's not M$!) and Mr. Grainger has prompted me to poke around into that territory. I'd vaguely looked into it for another project sometime ago, but it wasn't needed in the end.

There are a number of versions of Linux available for Mac users but I'm not in a position to recomend - it's down to personal choice.

For a PC user Linux is more of a sidestep, whereas for a Mac user it's more of a few major steps along with the (short version) 'received wisdom' that it's an alternate to M$ - it's already here on our system folders .............
(Ed: It is common to hear that the justification for Linux is that it is an alternative to MS. Indeed, I say it myself when I am not thinking too hard and someone wants a quick answer. It is also an easier to understand answer than the real one - the philosophy of free, (as in freedom, not cost), software. It would be hard to justify Linux to Macolytes as an alternative to Windows for the very reason Ken says. However, when it comes to freedom of software use, Apple is just as evil an empire as MS.)

For Mac owners with floppys drives there are disk images to download from the debian.org site, to enable trying Linux out. When I tried it out disk 1 was fine. Boots up up with a penguin lounging in front of a classic, instead of 'happy', Mac, but sad to say it required another floppy image with an archive in it. This required another 4K than there is on a floppy! - Oh Dear, says Ken, as things freeze up with a Kernal Panic.

There exists a means of having both a Linux and a nice normal Mac OS on your HD - by using an extension and a control panel called "BootX". This gives you a choice of Mac OS or Linux upon startup - a feature in MKLinux as well.

From my brief experiments it's clear that an install CD would be needed to continue any further with Linux.
(A non installing boot CD, like Mr. Grainger has for the PC, would be best as an intro)

MAGIC ROUNDABOUT

Linux requires a separate partition on your HD, not in Apple format - (shock horror!), but if you've used the Apple HD formatting utility you'll have most likely seen the option entitled 'A/UX '. This stands for Apple UniX, a concept from Mac's dawn that fizzled out leaving only its format option as a memorial.

These same formatting tools will only format an Apple approved SCSI HD, which for us older machine users isn't an ideal situation. Fear not, however, there exists patched versions of the tools to tackle any SCSI HD your budget can run to.

HD SC Setup 7.3.5 patcher
http://www.euronet.nl/u sers/ernstoud/hdpatch.html

HD SC Setup 3.0.1 (A/UX) formats everything that rotates. Other versions, like 7.3.5 (unpatched), only recognize Apple supplied drives.
http://www.euronet.nl/u sers/ernstoud/hdsetup.html

ON THE BUSES

Macs are friendly beasties - when you switch them on you get greeted with a smiley Mac Classic after the startup chime. (I expect the latest version of the OS has done away with it - boo hiss).

Bright & early one morning my 7300 was fired up and I went to put the kettle on. Upon my return the happy mac was still there - instead of the Toronto shoreline! I tried forced restarts but it was clear that nothing was going to go further. If it was an HD failure it would have manifest itself in not getting the happy mac, so it was time to get out the emergency CD to see what was going on. (My boot CD also contains Norton Utilies).

When a Mac is started up it looks for an active system folder in one of a number of places in the following sequence:

1/ Internal HD
2/ external HD
3/ floppy drive
4/ internal CD drive .

It took a while for it to abandon #1 and work through the sequence, so when I saw the boot CD screen I knew that it wasn't anything expensive, (in comparison that is!).

Something non fatal had happened to the HD, (unlike my IICi panic of a few years ago), as I was offered the choice of initializing it when the startup had finished - and instead of taking ages it was moments.

Taking this as a good sign I started running Norton Utilities on it to see if any files that I hadn't backed up recently could be salvaged. This took quite some time and, looking back, it was a waste of time.

In the end I did a clean install of OS8 and ran through a few restarts to make sure. I then put an OS8 boot floppy in and held down the 'C' key to enable startup from floppy /CD. Doing this I could use my 3 week old backup to put things back the way they were in OS8.6 .

The nearest thing in human terms was that my 7300 had had a stroke and a course of intensive therapy had cured things. The first thing to be done was, of course, to make a backup of things! Next was the creation of an OS8.6 boot CD with Norton and the patched formatters just in case .........

Having stuff backed up meant the fault was a nuisance, not a disaster as it so easily could have been -- important lesson for the day!

THE GOOD OLD DAYS

Time to put my Commodore hat on now. While checking through some 8050 disks I found two with the same deleted entry of a filename that was worth checking out. But, setting disk recovery onto them proved to be fruitless due to overwrites.

The Commodore disk drive stores the data in lumps, (sectors), with the first 2 bytes in each sector being a pointer to the next sector in the chain. Very simply put, the disk drive speeds up its reading of information by not putting the data in a single band around the disk. It skips a few sectors between each block of data so that by the time one data block is processed it will be in the right place to read the next block.

Having the starting point for the deleted file on the first disk, working out the probable sector locations to look at took a while - but it could be done. Searching along the paths turned up quite a lot of the sectors and they were block written to a fresh disk. Repeating the process on the other disk turned up the still remaining sectors of the mystery file. Luckily, there weren't any missing file sectors between the two disks and it was then just a matter of knitting the 2 threads together to recreate the original program. Unfortunately, the resulting file turned out to be a version of Spaceys, which was already in the library!


 

 

 

 


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