algorithm

\documentclass[10pt]{article}
\usepackage {algorithm}
\usepackage {algorithmic}

\begin{document}
\begin{algorithm}
\vspace{2mm}

\textbf{VARIABLES AND STRUCTURES}\\
$x$: references block, \textbar B \textbar: total cache size\\
$T1$,$T2$: partitions for a disk and a flash memory\\
$cumulated\_ref\_count$: cumulated reference count\\

\textbf{MAIN ALGORITHM}
\begin{algorithmic}[1]
    \STATE Initialize required variables and structures
    \STATE Determine the access pattern of each block if it is a sequential or random at every reference of blocks
    \STATE Increase $cumulated\_ref\_count$
    \STATE If a cache hit occurs in $T1$ (or $T2$)
    \STATE Move the block to the MRU in $T1$ (or $T2$)
    \STATE \hspace{4mm} Execute \textbf{H\_update}
    \STATE Else
    \STATE \hspace{4mm}Execute \textbf{List\_update}
    \STATE If $cumulated\_ref\_count = W$
    \STATE \hspace{4mm}Execute the \textbf{dynamic partitioning algorithm} in Fig. 4
\end{algorithmic}
\end{algorithm}

\end{document}