HEMA-HeDeDe

Here people collected their own controllers (Nemo-HDD) and were tormented
how to load the isdos. And it seems that Kondratyev was raving about the need
for a correct MBR...

Why reinvent the wheel long ago invented by IBM and MelkoMiagkie?

FAK:

Physically, a HDD can contain up to 4 partitions (aka Partition).
Information about the structure of the disk - *partition table* - stored in
/master boot record/ MBR (Master Boot Record) - sector 1,
cylinder 0, head 0. !!! I’m not sure here, but that’s what it says in the book.
I myself have always climbed through LBA, everything starts from 0 there!!!

On the computer, the MBR is loaded and launched...

But in addition to the bootloader, information about the partitions is stored in the MBR disk.

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

What can be done - drive the iS-DOS bootloader into the MBR and split
the screw into disks.

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

It is clear that if there are only 4 partitions, then even for a 100mb screw this is not enough.
But you can enter a special type of partition - “Extended iS-DOS partition”
which will contain iS-DOS disk descriptors. In short, everything
is similar to MS-DOS. MS-DOS itself will call such partitions non-dos partition.

Well, the loader will have to be in a FIXED POSITION ONiS-DOS
DISK read the file is_dos.sys into memory. I don’t know what to do with the length of is_dos.sys
. I also don’t know what to do with the overwritten is_dos.sys. However
there is no need to rewrite it - all the necessary drivers can be installed
using the program set.com in autoexec.bat.

Kirill Frolov. [ZX]

One Sunday, October 31, 1999 at 01:18:52, while wiping a hot modem
with a wet rag, I
noticed how Kirill Frolov and All were arguing on the topic HEMA-HeDeDe:

KF> Why reinvent the wheel that was long ago invented by IBM and FinelySoft?
KF> !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
KF> What can you do - drive the iS-DOS bootloader into the MBR and split
KF> the screw into disks.
KF> !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

You said that too late... In the current ROM in KAY seems to be looking for is_dos.sys, but
maybe I’m wrong... Of course, it’s much more correct to do it as you described here.
But who will change the ROM? And write software (which is in ROM)?

S!ncerely Yours,
Leonid Mishankov.

01 Nov 99 12:57, Leonid Mishankov wrote to Kirill Frolov:

KF>> !!!!!! What can you do - install the iS-DOS bootloader into the MBR and
KF>> split the screw into disks. !!!!!!!!!!!!!!!!!!!!!!!!!!!

LM> You said it too late... In the current ROM in KAY it seems to be looking for
LM> is_dos.sys, but maybe I’m wrong...

Most likely you’re not wrong. There, initially it just loaded from a fixed
position, and then the person doing it raved about searching.

LM> Of course, it is much more correct to do it as you described here.
LM> But who will change the ROM? And write software (which is in ROM)?

And get it - these controllers were installed anywhere, even in pentagons,
and there aren’t many of them in kayaks either. And people at the Pentagons don’t know how to load.

What can be done:

Write a tiny bootloader that will check for the presence of a screw and
load the MBR. ALL !

The bootloader can be pushed directly into TR-DOS, there is free space there.

Well, if it’s normal, then the Spectrum has long needed P.O.S.T., BIOS and then
only the bootloader.

Kirill Frolov. [ZX]

Who, who... whoever feels the urge to load is-dos from the screw, that will be it.
I did what I needed, strained, invented the wheel and use it. Although not at all
as they offer here, I like it, it’s very convenient.

All the best.
Sincerely, Roman.

31 Oct 1999 you wrote here:

KF> Here people collected their own controllers (Nemo-HDD) and were tormented
KF> how to load the isdos. And it seems that Kondratyev was raving about the necessity

That was a long time ago, I personally don’t suffer anymore. :)

...

RM> Who, who... whoever feels the urge to load is-dos from the screw, that will be it.
RM> I did what I needed, strained myself, invented the wheel and use it. Although
RM> is not
RM> at all
RM> as they offer here, but I like it, it’s very convenient.

Well... No one pulled your tongue... Tell me how you did it.

S!ncerely Yours,
Leonid Mishankov.

LM> Well... Nobody pulled your tongue... Tell me how you did it.

I already talked about it here.
1. An is-dos resident is created using is_res.com.
2. TR-DOS-prog SV_RMRM.B saves this resident image on a predetermined screw track (96 sectors, this place cannot be used). This is for the first
time, then, if you need to re-create the image on the screw, there is a resource sv_rmrm.com.
You can then launch this image TR-DOS-prog.
But it’s better to flash the ROM. MADROM and BASIC-48 are flashed with the boot procedure. And,
TR-DOS needs 5.13 for the resident to start.
Then you just press one button - and here is is-dos.
It is very desirable to have a CMOS clock, it stores the geometry of the propeller and the start
track, otherwise the whole thing will have to be tailored to a specific model of the propeller.

2KF: And there is an MBR, so if you make one, then tie it to Track 0 is not allowed - what if this track is broken? CMOS after allneeded.

16 Nov 99 16:22, Roman Milukov wrote to Leonid Mishankov:

RM> 2KF: And the MBR is found, so if you do it, you can’t link it to the 0th track
RM> - what if this track is broken? CMOS is still needed.

I have doubts...

Modern screws can move bad sectors - the likelihood of such
happening is much less.

The screw needs at least one sector, which will always have certain
coordinates and will contain information about dividing the screw into disks. Without it
if you have lost the piece of paper on which everything is written down, you can safely format
the screw again.

And if at least one sector should be non-movable, then why not
0? As an alternative, I can suggest searching for the MBR starting from sector
0 and beyond. That is if sector 0 does not contain the MBR signature at the end (55AAh),
then 1 sector is taken, then 2 sectors...

Kirill Frolov. [ZX]

KF> I have doubts...

KF> Modern screws can move broken sectors - the likelihood of this

How is this? When physically formatting a track, or what? :-/

KF> The screw needs at least one sector, which will always have
certain
KF> coordinates and will contain information about dividing the screw into disks. Without it
KF> if you have lost the piece of paper on which everything is written down, you can safely format the
KF> screw again.

Well, write this information down in a text file on the system disk so you don’t lose it. :)

KF> And if at least one sector should be non-movable, then why not
KF> 0? As an alternative, I can suggest searching for the MBR starting from sector
KF> 0 and beyond. That is if sector 0 does not contain the MBR signature at the end (55AAh),
KF> then 1 sector is taken, then 2 sectors...

On my old screw, the first 10 seconds with killed identifiers, for example.
If there is CMOS, then you simply don’t care, you can assign any that it
"MBR".
No, you can, of course, iterate through all the sectors in turn, starting from 0... But this
is not aesthetically pleasing.

KF>> Without it, if you lose the piece of paper on which everything is written down, you can
KF>> feel free to format the screw again.
RM> Well, write this information down in a text file on the system disk, so as not to
RM> lose it. :)

Well, what if there is a text file like this from another
screw on the screw’s disk???

It turns out that an arbitrary sequence of bits cannot be stored on the screw.

RM> for example. If there is CMOS, then you just don’t care, you can assign
RM> whatever it is “MBR”. No, you can, of course, go through all
RM> sectors one by one, starting from 0... But this is not aesthetically pleasing.

IMHO the most progressive option. Moreover, this can be done
only when the computer is turned on, and then the location of the ICBM can be stored in the brain.

Kirill Frolov. [ZX]