Try SpeedStor 6.5 - it should list the HDD parameters table in ROM BIOS...

Another software worth trying is Checkit Pro.

Grzyb wrote on 2023-11-02, 15:49:

Try SpeedStor 6.5 - it should list the HDD parameters table in ROM BIOS...
Another software worth trying is Checkit Pro.

There is no issues to find HDD matching C/H/S parameters, the problem is that I'm not sure that those HDD from list above will work with my model. As you see that the list of supported HDD from M290-25 is not equal to the M290-30, so in my case there may be another variants.
So, it would be better to find somebody with the same PC and ask what HDD is installed.

FWIW, just saw M290-20 listed for sale, with Conner CP3000.

But seriously, aren't all disks with geometry matching the list in ROM BIOS supposed to work?
Is there anything special about those Olivetti machines that makes them pickier than other PCs?

Grzyb wrote on 2023-11-02, 20:59:

FWIW, just saw M290-20 listed for sale, with Conner CP3000.

Thank you, not so big, but will be enough for this PC

Grzyb wrote on 2023-11-02, 20:59:

But seriously, aren't all disks with geometry matching the list in ROM BIOS supposed to work?

This geometry details were given for the another model and may not work for the M290-20.

Grzyb wrote on 2023-11-02, 20:59:

Is there anything special about those Olivetti machines that makes them pickier than other PCs?

No, I have couple of HDDs matching sizes and all of them didn't work on this Olivetti. There is no options to set the geometry in the BIOS

Was able to find application that can read BIOS and display all supported types. And those settings are slightly different from the M290-25 manual.
Here it is, put it there for the history purposes 😀 Now it will be easier to find proper drive.
Type 1: 968 Cyl 5H 17S
Type 2: 977 Cyl 10H 17S
Type 3: 762Cyl 8H 39S
Type 4: 750Cyl 8H 17 S

Susanin79 wrote on 2023-11-05, 14:53:

Was able to find application that can read BIOS and display all supported types.

But have you tried SpeedStor or Checkit Pro?
I want to know if that "Hard Disk Tech Specs" is any better than the above...

Beg my pardon, didn't know that SpeedStor can read the standard types from BIOS, as I always use a custom type. It was so easy 😀 And yes, SS shows the same table.
And for the Checkit Pro, I found 2 installation floppies, but I can not install it without the HDD.

So I tried the three programs on my 486...

Checkit Pro 1.11 lists some entries as "Extended or Invalid", while the other two can't see any problem with them...

Anyway, that Olivetti BIOS is really limited - only 4 predefined types.
Even the earliest IBM AT BIOS (01/10/84) supports 14 types.

I looked at the BIOS dump for the Olivetti and the HDD table starts at 0x1E401:

1Type1: C803 05 000000000000000000 C803 11 00
2Type 2: D103 0A 000000000000000000 D103 11 00
3Type 3: FA02 08 000000000000000000 FA02 27 00
4Type 4: EE02 08 000000000000000000 EE02 11 00

Using Type 1 as example:

968 Cylinders -> 0x03C8 so C803
5 Heads -> 0x05
17 Sectors -> 0x11

Should be able to replace one of those with the parameters of the disk you want, my suggestion is to use a CF card instead of an hdd.

You'll likely need to adjust the checksum of the binary but I can't find where it is, I thought it would be the last byte but something isn't adding up (no pun intended), the checksum of the whole document is not 00 so perhaps check if the dump has been made correctly or maybe it's a different algorithm and someone else could chime on this hopefully