A few questions

vbimport

#1

Hello!
There are a few things that I want to understand but I haven’t found any good information on the net.

My questions are as follow:

  • What exactly is firmware and what is it used for?
  • What does RAW-mode reading and writing mean?
  • What is a EFM-encoder? How does it work?
  • The physical signatures used by some CD-protections is not posible to recreate right? But it must be posible to read them, how can this be?
  • Exactly what is a sector? A special ammount of bytes?
  • What is a bad sector? (do not aswer a unreadable sector) why is it not readable if you do not use RAW-mode?

I hope someone can answer atleast a few of these questions. Sorry for my bad english, english isn’t my native language.


#2

Originally posted by XyliX
[B]Hello!
There are a few things that I want to understand but I haven’t found any good information on the net.

My questions are as follow:

  • What exactly is firmware and what is it used for?
  • What does RAW-mode reading and writing mean?
  • What is a EFM-encoder? How does it work?
  • The physical signatures used by some CD-protections is not posible to recreate right? But it must be posible to read them, how can this be?
  • Exactly what is a sector? A special ammount of bytes?
  • What is a bad sector? (do not aswer a unreadable sector) why is it not readable if you do not use RAW-mode?

I hope someone can answer atleast a few of these questions. Sorry for my bad english, english isn’t my native language. [/B]

  • Firmware is the link between hardware and interfacing. The firmware will set things that tell the hardware its supporting , how to behave. In general , Cd Writer firmware will give settings such as speed , writer temperature , vibration , etc.

  • http://knowhow.cdfreaks.com/article.php?ID=118

  • Check my explanation in the hardware forum

  • Depends entirely on the protection used , more info can be found in the clonecd forum. Thing to remember is that CD-R(W)'s are total different things than CD’s.

  • A sector is a part of the total pie that makes out the entire harddisk , floppy disk , cdrom of dvd rom. It contains a couple of bytes. The thing is that media has a given amount of sectors per system and a given amount of bytes per sector/

  • A bad sector is a sector that is marked (but necessary) “bad/unreadable” towards its File Allocation Table or file system. It is not readable because the reading program applies the standard reading techniques that the allocation tables tell the operating system or program to do. The RAW method does not use the standard reading techniques , rather ingnores them as much as possible.


#3

Thanks for the quick answer, I just got a followup question.

Originally posted by Mr. Belvedere
- A sector is a part of the total pie that makes out the entire harddisk , floppy disk , cdrom of dvd rom. It contains a couple of bytes. The thing is that media has a given amount of sectors per system and a given amount of bytes per sector/

Ok, so a CD (Let’s only speak CD sectors, not HDD or floppy disk etc) is divived into different sectors. Is there a fixed number of bytes in eact sector on a CD? In that case how big is a sector on a CD? And what is the data of a sector, is there only “pure data” or does each sector begin with a header etc? or e.g. a ID?

Thanks!


#4

Depends on the chosen format , for a starting reference , check here (Chapter : Sectors to a digital data track).