Chapter 12: Windows under the Hood (A+ Study Notes)

A+

Study Notebook

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You can find my complete study notes in Google Docs format below: https://docs.google.com/document/d/1zcKLWfsns1tqzmXtVRJbcd9NqfaEcjifgIo-oJIbEgc/edit?usp=sharing

References:
M. MEYERS, 2019.  CompTIA A+ All-in-One Exam Guide. 10th ed.

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Chapter 12: Windows under the Hood

• Registry (huge database that stores everything about the PC: hardware, network, user preferences, file types , passwords, desktop colors etc. ) 

• No registry = System won’t boot
• /SystemRoot/System32/config and each user account 
• Registry Components:

• HKEY_CLASSES_ROOT (defines class objects, or files on the system)

• HKEY_CURRENT_USER (personalisation)

• HKEY_USERS (personalisation)

• HKEY_LOCAL_MACHINE (config for apps and devices) 

• HKEY_CURRENT_CONFIG

·         Values must have a defined type of data they store:

·         String value (you can put anything in it) 

·         Binary value (1s and 0s)

·         DWORD value (Binary but limit is 32 bits)

·         QWORD value (Binary but limited to 64 bits)

·         How to access Registry Editor:

·         Regedit 

·         Reg

·         Regsvr32 (only for Adding DLL files)

·         The Boot Process: BIOS vs UEFI 

·         BIOS: Boot order to scan a hard drive for a Master Boot Record (MBR). MBR holds system boot code that scans partition table for the system, and loads its boot sector. Boot Sector contains code that simply points the boot process toward a file called bootmgr.

·         UEFI: it straight away loads bootmgr

·         When bootmgr starts: it reads data from BCD (Boot Configuration Data) file, which contains info about various OSes installed on the system, and info on how to load them (bootstrap). When OS is selected, bootmgr loads winload.exe, which loads systems kernel (ntoskrnl.exe) (by loading into memory: hardware abstraction layer, the system Registry, and the drivers). Finally, OS itself takes over and starts various processes, services, applications. 

·         Applications, Processes, and Services 

·         When Applications are started they are loaded into RAM as a process. CPU reads the process, and then tells the CPU which chunk of code to run. 

·         Processes run invisibly in the background, providing support roles. 

·         Task Manager: 

·         Applications: show all running apps on the system

·         Processes: everything is a process

·         Services: services.msc

·         net start servicename (to start the service from within command line)

·         net stop servicename 

·         Performance

·         Networking and Users 

·         Resource Monitor (Task Manager on steroids) 

·         Performance Tools 

·         Performance Monitor (perform.msc): allows resource tracking over time 

·         Component Services: COM, DCOM, COM+

·         Enables programmers to share data objects (an element of programs) between applications on a single computer or a network . 

·         ODBC Data Sources: idea of shared databases.

·         ODBC (Open Database Connectivity) - coding standard that enables programmers to write databases and the applications that use them in a way that they can query ODBC, without any concern about what app or OS is used. 

·         ODBC Data Source Administrator: which enables you to create DSNs (Data Source Names) that point ODBC to a database.