Detailed Report on Android, NTFS, and EXT4 File System Architectures

This report delves into the intricacies of file systems, focusing on Android, NTFS, and EXT4. It begins with an introduction to file systems, explaining their role in managing data storage and access. The report then examines the Android file system, covering its directory structure, partitions, and the use of SD cards. Following this, it explores the NTFS file system, discussing its features such as journaling, metadata support, and security enhancements. The EXT4 file system is also analyzed, highlighting its scalability, allocation features, and performance optimizations. The report concludes by summarizing the key aspects of each file system, emphasizing their importance in modern computing environments. The paper provides an overview of file system functionalities, including file naming, storage management, access rules, metadata, and privileges, concluding with the file system's role in managing data storage and access.

Running head: FILE SYSTEM
FILE SYSTEM
Name of the Student
Name of the University
Author Note

FILE SYSTEM 1
Table of Contents
Introduction:...............................................................................................................................2
Android file system:...................................................................................................................2
The sd card and ext-sd card Partitions:..................................................................................3
NTFS file system:......................................................................................................................4
EXT4 System:............................................................................................................................5
Main features:.........................................................................................................................5
Allocation features:................................................................................................................6
Conclusion:................................................................................................................................6
References:.................................................................................................................................7

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Introduction:
The file system is a procedure that is able to manage where and how data on a hard
disk or typically a storage disk is accessed, stored and managed. This is a logical disk
component which can manage the internal operations of a disk as this relates to one computer
as well as it is abstract to a user (Heuser et al., 2016). The file systems manage typically the
operations like file naming, management of storage, folders or directories, access rules,
metadata and privileges. The purpose of this paper is to discuss about the commonly used file
systems such as android file system, NTFS and EXT4 file system.
Android file system:
The directories and partitions of the system are protected as well as unless a device is
rooted, normally a user cannot access to the some of the file managers (Lee et al., 2015). The
partitions as well as the physical disks appear under the root as a directory as well as it does
not having a drive letter such as in windows. Normally, Android does not come with a default
file manager, so the user has to install an external file manager application for locating and
managing the folders and files.

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(Figure: Android file system structure)
The sd card and ext-sd card Partitions:
The sd card partition is the actual primary storage area for the files and user data. This
can also contain App data as well as setting (Allix et al., 2016). The sd card partition always
exist even though if there will be no external sd card. This remains in the internal partition.
After opening the sdcard directory. The sd card directory looks like this:
(Figure: Android SD card directory)
The directories and files can contain films, pictures, downloads and along with that App
setting and data. The files can also be viewed from the PC by making connection between PC
and device with the help of a USB cable (Jaffer et al., 2019). The external sd card uses
FAT32, FAT or exFAT formats. Though, most of the devices support FAT32 and FAT,
however the support for the exFAT file system is limited.
Card Type Card Type File System Max Capacity

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SD FAT 2GB
SDHC FAT32 32GB see Note
SDXC exFAT 2TB
The size limit of windows format is 32 GB, it can be larger however that needs to be
formatted by using external tools.
NTFS file system:
The New Technology File System (NTFS) is file system which is journaling and is
developed by Microsoft starting with Windows NT 3.1. It is the file system which is default
to the family of Windows NT. NTFS has got several improvements in the technical area over
the file system that is the File Allocation Table (FAT) and the High-Performance File System
(HPFS). It has the support that is improved for the metadata and the data structures that are
advanced so as to improve the performance, disk space use and reliability (Nordvik, Toolan,
and Axelsson, 2019). The extensions that are additional are more elaborate security systems
which are based on the file system journaling as well as the lists of access control. NTFS is
supported in other operating system and also in other desktops. The BSD as well as Linux
have an open source NTFS driver which is free of cost. It is called the NTFS-3G. It has both
the functions of both read and write. The Mac operating system has only read only support
for the NTFS. The features of the NTFS are as follows:
 It uses a directory called the B-Tree so as to keep track of the clusters of files.
 The information that is about a cluster of a file as well as other data are stored with
each cluster. It is not a table that is governing.

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 It is a support for files that are very large.
 Has a feature of compression of integrated file.
 It has support for the names which are based on Unicode.
It has the support for the file names that are long.
 It gives security of data on the fixed as well as the fixed disks.
The working of the NTFS is that when a hard drive is formatted, the hard disk is divided
into several parts which are known as the partitions of the total space of the hard disk.
Within each of the divisions the operating keeps the track of each of the files that is being
stored by that operating system (Jannen et al.,2015). Every file is usually stored on the
hard drive of the system in one more cluster of a uniform size that is predefined. Using
the NTFS, the cluster size ranges from 512 bytes to 64 kilobytes. The Windows NT
provides a size of the cluster that is recommended for any size of the drive.
EXT4 System:
Main features:
The EXT4 file system is one of the scalable extensions of the EXT3 file system that
was the default file system of the Red Hat Enterprise of Linux based Operating System. In
the Red Hat Enterprise Linux 6, the default file system is Ext4, this has the ability to support
file systems and files up to 16 TB in size (Xu and Swanson, 2016). This also having the
support of sub directories that is unlimited in number. For performing an fsck the EXT4 file
system have to be unmounted. Extents are used by the EXT4 file system that is having the
ability to improve performance at the time of using of the files that are larger in size as well
as it reduces the metadata for the files that are larger (Chen et al., 2015). In addition, the
EXT4 file systems labels also the unallocated group of blocks as well as selection of inode
table accordingly that gives the allowance to them to be skipped at the time of checking of

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the file system. It makes for the quicker checks of the file systems that becomes much
beneficial as soon as the size of the file system grows.
Allocation features:
The features of the EXT4 file system, there are the following allocation schemes:
 Delayed allocation
 Persistent pre-allocation
 Multi-block allocation
 Stripe-aware allocation.
Because of the delays in allocation as well as the other optimizations in the performance. The
behaviour of the EXT4 file system of writing files to the disk in totally different form the
EXT3 file system. In the EXT4 file system, at the time a program started writing to the file
system, this is not guaranteed that, it is to be on the disk unless the issues that are related to
the program an fsync () call afterwards.
Conclusion:
Thus, it can be concluded from the above report that the file systems are actually This
a logical disk component which can manage the internal operations of a disk as this relates to
one computer as well as it is abstract to a user. The file systems manage typically the
operations like file naming, management of storage, folders or directories, access rules,
metadata as well as privileges. It has the support that is improved for the metadata and the
data structures that are advanced so as to improve the performance, disk space use and
reliability. The extensions that are additional are more elaborate security systems which are
based on the file system journaling as well as lists of access control.

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References:
Allix, K., Bissyandé, T.F., Klein, J. and Le Traon, Y., 2016, May. Androzoo: Collecting
millions of android apps for the research community. In 2016 IEEE/ACM 13th Working
Conference on Mining Software Repositories (MSR) (pp. 468-471). IEEE.
Chen, H., Ziegler, D., Chajed, T., Chlipala, A., Kaashoek, M.F. and Zeldovich, N., 2015,
October. Using Crash Hoare logic for certifying the FSCQ file system. In Proceedings of the
25th Symposium on Operating Systems Principles (pp. 18-37). ACM.
Heuser, S., Negro, M., Pendyala, P.K. and Sadeghi, A.R., 2016, February. Droidauditor:
Forensic analysis of application-layer privilege escalation attacks on android. In Proceedings
of the 20th international conference on financial cryptography and data security (pp. 1-12).
Jaffer, S., Maneas, S., Hwang, A. and Schroeder, B., 2019. Evaluating File System Reliability
on Solid State Drives. In 2019 {USENIX} Annual Technical Conference ({USENIX}{ATC}
19) (pp. 783-798).
Jannen, W., Yuan, J., Zhan, Y., Akshintala, A., Esmet, J., Jiao, Y., Mittal, A., Pandey, P.,
Reddy, P., Walsh, L. and Bender, M., 2015. BetrFS: A right-optimized write-optimized file
system. In 13th {USENIX} Conference on File and Storage Technologies ({FAST} 15) (pp.
301-315).
Lee, C., Sim, D., Hwang, J. and Cho, S., 2015. F2FS: A new file system for flash storage.
In 13th {USENIX} Conference on File and Storage Technologies ({FAST} 15) (pp. 273-286).
Nordvik, R., Toolan, F. and Axelsson, S., 2019. Using the object ID index as an investigative
approach for NTFS file systems. Digital Investigation, 28, pp.S30-S39.

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Xu, J. and Swanson, S., 2016. {NOVA}: A Log-structured File System for Hybrid
Volatile/Non-volatile Main Memories. In 14th {USENIX} Conference on File and Storage
Technologies ({FAST} 16) (pp. 323-338).