diff --git a/bin/photos-diff.ts b/bin/photos-diff.ts
index 7f1fcf4..d0de8ff 100755
--- a/bin/photos-diff.ts
+++ b/bin/photos-diff.ts
@@ -2,7 +2,7 @@
 
 import { execSync, spawn } from 'child_process';
 import { createHash } from 'crypto';
-import { readFileSync, statSync, writeFileSync } from 'fs';
+import { createReadStream, statSync, writeFileSync } from 'fs';
 import { parseArgs } from 'util';
 import Redis from 'iovalkey';
 import { createInterface } from 'readline';
@@ -11,6 +11,15 @@ const CACHE_TTL = 3600; // 1 hour
 const CACHE_PREFIX_ANDROID = 'photo-sync:android:';
 const CACHE_PREFIX_LOCAL = 'photo-sync:local:';
 
+function showProgress(current: number, total: number, startTime: number, prefix: string): void {
+  const elapsed = Date.now() - startTime;
+  const avgTime = elapsed / current;
+  const remaining = total - current;
+  const eta = Math.round((avgTime * remaining) / 1000);
+  const etaStr = eta > 60 ? `${Math.floor(eta / 60)}m ${eta % 60}s` : `${eta}s`;
+  process.stdout.write(`\r${prefix} Progress: ${current}/${total} files | ETA: ${etaStr}     `);
+}
+
 interface FileInfo {
   path: string;
   size: number;
@@ -33,7 +42,7 @@ function parseArguments() {
   });
 
   if (!values.local || !values.android) {
-    console.error('Usage: ./photo-backup-checker.ts --local DIR --android DIR');
+    console.error('Usage: ./photos-diff.ts --local DIR --android DIR');
     process.exit(1);
   }
 
@@ -84,18 +93,7 @@ async function getLocalFiles(dir: string, redis: Redis): Promise<FileInfo[]> {
         await redis.setex(cacheKey, CACHE_TTL, JSON.stringify({ size: stat.size }));
       }
 
-      // Progress and ETA
-      const processed = i + 1;
-      const elapsed = Date.now() - startTime;
-      const avgTime = elapsed / processed;
-      const remaining = files.length - processed;
-      const eta = Math.round((avgTime * remaining) / 1000);
-
-      const etaStr = eta > 60
-        ? `${Math.floor(eta / 60)}m ${eta % 60}s`
-        : `${eta}s`;
-
-      process.stdout.write(`\r📁 Progress: ${processed}/${files.length} files | ETA: ${etaStr}     `);
+      showProgress(i + 1, files.length, startTime, '📁');
     } catch (err) {
       console.error(`\n❌ Error reading local file: ${file}`);
       throw err;
@@ -131,11 +129,11 @@ async function getAndroidFiles(dir: string, redis: Redis): Promise<FileInfo[]> {
   const fileInfos: FileInfo[] = [];
   const startTime = Date.now();
 
-  const BATCH_SIZE = 50;
+  const STAT_BATCH_SIZE = 50;
   let processed = 0;
 
-  for (let i = 0; i < files.length; i += BATCH_SIZE) {
-    const batch = files.slice(i, i + BATCH_SIZE);
+  for (let i = 0; i < files.length; i += STAT_BATCH_SIZE) {
+    const batch = files.slice(i, i + STAT_BATCH_SIZE);
 
     // Check cache first for this batch
     const cachedResults: FileInfo[] = [];
@@ -214,18 +212,8 @@ async function getAndroidFiles(dir: string, redis: Redis): Promise<FileInfo[]> {
       }
     }
 
-    // Progress and ETA
     if (processed > 0) {
-      const elapsed = Date.now() - startTime;
-      const avgTime = elapsed / processed;
-      const remaining = files.length - processed;
-      const eta = Math.round((avgTime * remaining) / 1000);
-
-      const etaStr = eta > 60
-        ? `${Math.floor(eta / 60)}m ${eta % 60}s`
-        : `${eta}s`;
-
-      process.stdout.write(`\r📊 Progress: ${processed}/${files.length} files | ETA: ${etaStr}     `);
+      showProgress(processed, files.length, startTime, '📊');
     }
   }
 
@@ -233,11 +221,15 @@ async function getAndroidFiles(dir: string, redis: Redis): Promise<FileInfo[]> {
   return fileInfos;
 }
 
-function sha256Local(path: string): string {
+async function sha256Local(path: string): Promise<string> {
   const hash = createHash('sha256');
-  const data = readFileSync(path);
-  hash.update(data);
-  return hash.digest('hex');
+  const stream = createReadStream(path);
+
+  return new Promise((resolve, reject) => {
+    stream.on('data', (data) => hash.update(data));
+    stream.on('end', () => resolve(hash.digest('hex')));
+    stream.on('error', reject);
+  });
 }
 
 function sha256Android(path: string): string {
@@ -274,11 +266,11 @@ async function calculateHashes(
 
   if (source === 'android') {
     // Batch processing for Android
-    const BATCH_SIZE = 20;
+    const HASH_BATCH_SIZE = 20;
     let processed = 0;
 
-    for (let i = 0; i < files.length; i += BATCH_SIZE) {
-      const batch = files.slice(i, i + BATCH_SIZE);
+    for (let i = 0; i < files.length; i += HASH_BATCH_SIZE) {
+      const batch = files.slice(i, i + HASH_BATCH_SIZE);
 
       // Check cache first
       const needHash: FileInfo[] = [];
@@ -349,17 +341,7 @@ async function calculateHashes(
         }
       }
 
-      // Progress and ETA
-      const elapsed = Date.now() - startTime;
-      const avgTime = elapsed / processed;
-      const remaining = totalFiles - processed;
-      const eta = Math.round((avgTime * remaining) / 1000);
-
-      const etaStr = eta > 60
-        ? `${Math.floor(eta / 60)}m ${eta % 60}s`
-        : `${eta}s`;
-
-      process.stdout.write(`\r🔐 Progress: ${processed}/${totalFiles} files | ETA: ${etaStr}     `);
+      showProgress(processed, totalFiles, startTime, '🔐');
     }
   } else {
     // Local files - keep sequential for now
@@ -374,25 +356,13 @@ async function calculateHashes(
           const data = JSON.parse(cached);
           if (data.hash) {
             file.hash = data.hash;
-
-            // Progress and ETA
-            const processed = i + 1;
-            const elapsed = Date.now() - startTime;
-            const avgTime = elapsed / processed;
-            const remaining = totalFiles - processed;
-            const eta = Math.round((avgTime * remaining) / 1000);
-
-            const etaStr = eta > 60
-              ? `${Math.floor(eta / 60)}m ${eta % 60}s`
-              : `${eta}s`;
-
-            process.stdout.write(`\r🔐 Progress: ${processed}/${totalFiles} files | ETA: ${etaStr} (cached)     `);
+            showProgress(i + 1, totalFiles, startTime, '🔐');
             continue;
           }
         }
 
         // Compute hash
-        file.hash = sha256Local(file.path);
+        file.hash = await sha256Local(file.path);
 
         // Update cache with hash
         await redis.setex(cacheKey, CACHE_TTL, JSON.stringify({ size: file.size, hash: file.hash }));
@@ -402,18 +372,7 @@ async function calculateHashes(
         throw err;
       }
 
-      // Progress and ETA
-      const processed = i + 1;
-      const elapsed = Date.now() - startTime;
-      const avgTime = elapsed / processed;
-      const remaining = totalFiles - processed;
-      const eta = Math.round((avgTime * remaining) / 1000);
-
-      const etaStr = eta > 60
-        ? `${Math.floor(eta / 60)}m ${eta % 60}s`
-        : `${eta}s`;
-
-      process.stdout.write(`\r🔐 Progress: ${processed}/${totalFiles} files | ETA: ${etaStr}     `);
+      showProgress(i + 1, totalFiles, startTime, '🔐');
     }
   }
 
@@ -440,6 +399,22 @@ function findDuplicates(files: FileInfo[]): Record<string, string[]> {
   return duplicates;
 }
 
+async function checkDependencies(redis: Redis): Promise<void> {
+  try {
+    await redis.ping();
+  } catch (err) {
+    console.error('❌ Redis is not available');
+    process.exit(1);
+  }
+
+  try {
+    execSync('adb version', { stdio: 'ignore' });
+  } catch (err) {
+    console.error('❌ ADB is not available');
+    process.exit(1);
+  }
+}
+
 async function main() {
   const { localDir, androidDir } = parseArguments();
 
@@ -454,6 +429,8 @@ async function main() {
   });
 
   try {
+    await checkDependencies(redis);
+
     // Step 1: Collect file lists
     const localFiles = await getLocalFiles(localDir, redis);
     const androidFiles = await getAndroidFiles(androidDir, redis);