bcal

bcal (Byte CALculator) is a command-line utility for storage conversions and calculations. Storage, hardware and firmware developers work with numerical calculations regularly e.g., storage unit conversions, address calculations etc. If you are one and can't calculate the hex address offset for (512 - 16) MiB immediately, or the value when the 43^rd bit of a 64-bit address is set, bcal is for you.

Though it started with storage, the scope of bcal isn't limited to the storage domain. Feel free to raise PRs to simplify other domain-specific numerical calculations so it can evolve into an engineer's utility.

bcal follows Ubuntu's standard unit conversion and notation policy. Only 64-bit operating systems are supported.

Table of Contents

• Features
• Installation
  • Dependencies
  • From a package manager
  • Release packages
  • From source
• Usage
  • cmdline options
  • Operational notes
• Examples
• Testing
• Copyright

Features

• evaluate arithmetic expressions involving storage units
• convert to IEC/SI standard data storage units
• show the address in bytes
• show address as LBA:OFFSET
• convert CHS to LBA and vice versa
• show binary, decimal and hex representation of a number
• custom sector size, max heads/cylinder and max sectors/track
• minimal dependencies

Installation

Dependencies

bcal is written in C and depends on standard libc and GCC libquadmath.

From a package manager

• AUR
• Debian Sid
• Ubuntu
• Ubuntu PPA

Release packages

Packages for Arch Linux, CentOS, Fedora and Ubuntu are available with the latest stable release.

From source

If you have git installed, clone this repository. Otherwise, download the latest stable release or development version (risky).

Install to default location (/usr/local):

$ make
$ sudo make install

To uninstall, run:

$ sudo make uninstall

PREFIX is supported, in case you want to install to a different location.

Usage

cmdline options

usage: bcal [-c N] [-f FORMAT] [-s bytes] [-d] [-h]
            [expression] [N unit]

Perform storage conversions and calculations.

positional arguments:
 expression  evaluate storage arithmetic expression
             +, -, *, / with decimal inputs supported
             unit can be multiplied or divided by +ve integers
             units can be added or subtracted from each other
             Examples:
               bcal "(5kb+2mb)/3"
               bcal "5 tb / 12"
               bcal "2.5mb*3"
 N [unit]    capacity in B/KiB/MiB/GiB/TiB/kB/MB/GB/TB
             see https://wiki.ubuntu.com/UnitsPolicy
             default unit is B (byte), case is ignored
             N can be decimal or '0x' prefixed hex value

optional arguments:
 -c N        show +ve integer N in binary, decimal and hex
 -f FORMAT   convert CHS to LBA or LBA to CHS
             formats are hyphen-separated
             LBA format:
               starts with 'l':
               lLBA-MAX_HEAD-MAX_SECTOR
             CHS format:
               starts with 'c':
               cC-H-S-MAX_HEAD-MAX_SECTOR
             omitted values are considered 0
             FORMAT 'c-50--0x12-' denotes:
               C = 0, H = 50, S = 0, MH = 0x12, MS = 0
             FORMAT 'l50-0x12' denotes:
               LBA = 50, MH = 0x12, MS = 0
             default MAX_HEAD: 16, default MAX_SECTOR: 63
 -s bytes    sector size [default 512]
 -m          show minimal output (e.g. decimal bytes)
 -d          enable debug information and logs
 -h          show this help and exit

Operational notes

• Expression: An expression must be within double quotes. Inner spaces are ignored. A storage unit can only be divided or multiplied by plain integers. Only storage units can be used for addition and subtraction.
• N [unit]: N can be a decimal or '0x' prefixed hex value. unit can be B/KiB/MiB/GiB/TiB/kB/MB/GB/TB following Ubuntu policy. Default is byte. As all of these tokens are unique, unit is case-insensitive.
• Only decimal is recognized in expressions. Decimal and hex numeric representations are recognized for unit conversions. Decimal, hex, binary and octal are recognized for all other operations.
• Syntax: Prefix hex inputs with 0x, binary inputs with 0b, octal inputs with 00.
• No negative arguments allowed. Input limits are unsigned long long and double.
• Fractional bytes do not exist, because they can't be addressed. bcal shows the floor value of non-integer bytes.
• CHS and LBA syntax:
  • LBA: lLBA-MAX_HEAD-MAX_SECTOR [NOTE: LBA starts with l (case ignored)]
  • CHS: cC-H-S-MAX_HEAD-MAX_SECTOR [NOTE: CHS starts with c (case ignored)]
  • Format conversion arguments must be hyphen separated.
  • Any unspecified value, including the one preceding the first - to the one following the last -, is considered 0 (zero).
• Default values:
  • sector size: 0x200 (512)
  • max heads per cylinder: 0x10 (16)
  • max sectors per track: 0x3f (63)

Examples

1. Evaluate arithmetic expression of storage units.

   $ bcal "(5kb+2mb)/3"
   $ bcal "5 tb / 12"
   $ bcal "2.5mb*3"
   

2. Convert storage capacity to other units and get address, LBA.

   $ bcal 20140115 b
   $ bcal 0x1335053 B
   $ bcal 0xaabbcc kb
   $ bcal 0xdef Gib
   

   Note that the units are case-insensitive.

3. Convert storage capacity, set sector size to 4096 to calculate LBA.

   $ bcal 0xaabbcc kb -s 4096
   

4. Convert LBA to CHS.

   $ bcal -f l500
   $ bcal -f l0x600-18-0x7e
   $ bcal -f l0x300-0x12-0x7e
   

5. Convert CHS to LBA.

   $ bcal -f c10-10-10
   $ bcal -f c0x10-0x10-0x10
   $ bcal -f c0x10-10-2-0x12
   $ bcal -f c-10-2-0x12
   $ bcal -f c0x10-10--0x12
   

6. Show binary, decimal and hex representations of a number.

   $ bcal -c 20140115
   $ bcal -c 0b1001100110101000001010011
   $ bcal -c 0x1335053
   

7. Help and additional information.

   $ man bcal
   $ bcal -h
   

Testing

Due to the nature of the project, it's extremely important to test existing functionality before raising any PR. bcal has several test cases written in test.py. To execute the test cases locally, install pytest and run:

$ make
$ python3 -m pytest test.py

Copyright

Copyright © 2016-2017 Arun Prakash Jana