🧹IODD TRIM Tool
User manual for the IODD TRIM Tool, a utility to maintain and optimize external USB SSD performance.
Platform: Windows 64-bit License: Freeware
1. Overview
The IODD TRIM Tool is a Windows-exclusive application designed to send TRIM commands to external SSDs connected via a USB-SATA bridge.
While Windows automatically performs TRIM on internal SATA/NVMe SSDs, this automatic function does not work for external SSDs connected through a USB bridge. This tool is designed to maintain the performance and extend the lifespan of such external SSDs.
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Key Features
Full Device TRIM: Sends the TRIM command to the entire SSD area.
Free Space Only TRIM: Performs TRIM only on empty space, preserving existing files.
ATA Pass-Through Detection: Automatically checks if the USB bridge supports ATA Pass-Through and TRIM.
Real Test: Verifies if TRIM is actually working by performing a file write/delete/verify sequence.
Drive Inspection: Provides detailed information on disk partitions, volumes, and free space.
Dry Run Mode: Simulates the process without sending actual TRIM commands.
8 Languages Supported: Korean, English, Japanese, Simplified Chinese, Spanish, German, French, and Russian.
2. System Requirements
OS
Windows 10 / 11 (64-bit)
Privileges
Administrator privileges required (needed for SCSI Pass-Through)
Connection
SSD connected via a USB-SATA bridge
Protocol
BOT (Bulk-Only Transport) recommended
Important: You must run the application with Administrator privileges. Standard user permissions cannot send SCSI Pass-Through commands to the disk.
3. What is TRIM?
TRIM is an ATA command (DATA SET MANAGEMENT, 0x06) that tells the SSD which data blocks are no longer in use.
Benefits of TRIM
Maintains Write Performance: Pre-emptively secures empty blocks to prevent write speed degradation.
Extends SSD Lifespan: Reduces unnecessary write/erase cycles, minimizing NAND wear.
Consistent Response Times: Maintains stable performance even after long periods of use.
Efficient Space Management: Optimizes the SSD controller's internal garbage collection.
When should you use TRIM?
After deleting a large number of files.
When the SSD's write speed has noticeably slowed down.
After using a USB external SSD for a long time without TRIM.
When the OS does not support automatic TRIM for USB-connected SSDs.
4. UI Layout
The app consists of a top toolbar and 3 main tabs.
5. Top Toolbar
IODD Products
Opens the IODD product page (Amazon) in your browser.
IODD Manual
Opens the IODD help site (help.iodd.kr) in your browser.
License
Displays a popup with freeware license information.
TRIM Info
Displays a popup explaining the benefits and timing of TRIM.
Language Selection
Changes the app's UI language (dropdown on the top right).
6. Execute TRIM Tab
This is the main tab where you send TRIM commands to the selected disk.
6.1 Disk Selection
Select the target disk from the dropdown menu at the top. Each item displays the following information:
PD8 | Samsung SSD 860 | 465.8 GiB | BOT | O:(FAT32) | TRIM:YES
PD Number: Physical Drive number
Model Name: SSD model
Capacity: Total disk capacity (GiB)
Protocol: BOT / UAS / Non-USB
Volume: Drive letter + File system
TRIM Support: TRIM:YES / TRIM:NO / APT:N/A
You can rescan the disk list using the Refresh button.
6.2 Disk Info Memo
When a disk is selected, detailed information appears in the memo box below:
Model, Serial, Capacity, Transfer Protocol
Volume info (File system, Cluster size, Offset, Partition length in GiB)
ATA Pass-Through support status
TRIM Capable status
ATA Model, Firmware info
6.3 TRIM Mode
Full Device TRIM
Sends TRIM to the entire disk. ALL data will be permanently deleted.
Free Space Only
Trims only the empty space on the file system. Existing files are preserved.
Warning: Full Device TRIM permanently deletes all data on the disk. Be sure to back up your data before using this mode.
6.4 Options
Dry Run
Simulates the operation without sending actual TRIM commands.
OFF
Flush Volumes
Flushes the volume buffers before performing TRIM.
OFF
Init after TRIM
Initializes the disk to GPT/MBR after TRIM is complete.
None
6.5 Advanced Settings
Checking the Show Advanced Settings box reveals additional options:
Timeout (ms)
Timeout duration for each TRIM batch.
20,000ms
Retry
Number of retries upon failure.
3
Batch Entries
Number of TRIM ranges to send at once.
32
Batch Limit
Maximum number of batches (1, 10, 100, All).
All
Allow System Disk
Allows TRIM on the OS system disk.
OFF
Mask Serial
Masks the serial number in logs.
ON
6.6 Execution
Select the disk.
Select the TRIM mode.
Click the Start button.
The progress will be shown on the progress bar and status bar.
A success/failure popup will appear upon completion.
You can stop an ongoing TRIM by clicking the Cancel button.
6.7 BOT Notice
You can view guidance regarding the USB bridge device's protocol. The UAS (USB Attached SCSI) protocol often blocks ATA Pass-Through, so connecting via the BOT protocol is recommended.
7. Drive Inspect Tab
Investigates detailed partition and volume information of the selected disk.
Features
Run Inspection: Retrieves detailed volume information for the selected disk.
Export Free Space CSV: Outputs the free space ranges as a CSV file.
Displayed Information
Total space, Used space, Free space
Partition number by volume, Drive letter, File system
Cluster size, Partition offset, Partition length
Free Space support status
8. Real Test Tab
Verifies whether TRIM is actually functioning on the SSD through a file write/delete/verify process.
Note: It is not mandatory to run the Real Test for standard TRIM usage. This feature is intended to verify if the USB bridge controller and this software properly execute TRIM on your specific SSD. If verification is needed, running it once is sufficient. The time required depends on the disk capacity and USB speed, taking approximately 6 hours for a 1TB SSD.
8.1 Test Procedure (STEP 1~4)
STEP 1
Fill Files
Fills 1/3 of the remaining capacity with 500MB random files.
STEP 2
Delete + TRIM
Deletes 1 in every 10 files → Flushes → Extracts Free Space CSV → Performs Free-space TRIM.
STEP 3
Additional Fill
Fills the remaining capacity with 1GB random files (leaving about 1GB of free space).
STEP 4
Integrity Verify
Verifies the CRC integrity of the 500MB files.
8.2 Options
Start Step
The step number to start from (1~4).
End Step
The step number to end at (1~4).
Wait on Drop
Wait time (minutes) if write speed drops sharply. Set to 0 to disable.
8.3 Buttons
Start
Begins the entire test (STEP 1~4).
Verify Only
Only verifies the CRC integrity of existing files (corresponds to STEP 4).
Stop
Immediately halts the ongoing test.
Delete Test Folder
Deletes the temporary files/folders used for the test.
Export FileMap
Exports the physical location map of the test files as a CSV.
8.4 Status Display
Status: The currently executing step.
Speed: Real-time read/write speed (MB/s).
Elapsed: Total elapsed time.
Step: Elapsed time for the current step.
8.5 Test Completion
Upon completion, a success/failure popup appears:
Success: If all file CRCs match, it means TRIM is functioning correctly.
Failure: If a CRC mismatch occurs, there may be data corruption after TRIM.
Cancelled: If the user pressed the Stop button.
9. Multilingual Support
You can change the language from the dropdown in the top right corner of the app. The OS language is automatically detected and set as the default.
Korean
한국어
English
English
Japanese
日本語
Simplified Chinese
简体中文
Spanish
Español
German
Deutsch
French
Français
Russian
Русский
10. Frequently Asked Questions (FAQ)
Q: It says ATA Pass-Through is not supported.
This happens when the USB bridge controller does not support ATA Pass-Through. It mostly occurs when connected via the UAS protocol. Switch to the BOT protocol, or use a USB bridge that supports ATA Pass-Through (e.g., JMicron JMS578, ASMedia ASM1153E, etc.).
Q: It displays TRIM:NO.
This means ATA Pass-Through is supported, but the SSD itself does not support TRIM. This happens with very old SSDs or traditional HDDs. TRIM is a command exclusively for SSDs.
Q: Free Space Only TRIM fails with a "No free-space bitmap ranges available" error.
This occurs when the file system bitmap cannot be read. Ensure that you are using a supported file system (NTFS, FAT32).
Q: The disk is not recognized after a Full Device TRIM.
After a full TRIM, the partition table may be deleted. If you set the Init after TRIM option to GPT or MBR, it will automatically initialize the disk afterward.
Q: I am getting an error even though I ran it with Administrator privileges.
Some antivirus software may block SCSI Pass-Through commands. Try temporarily disabling your antivirus and run it again.
11. Troubleshooting
Disk does not appear in list
Bad USB cable or not connected
Check USB connection and refresh
"Admin Privileges Required" error
Ran with standard user rights
Right-click app → "Run as Administrator"
APT:N/A displayed
USB bridge lacks ATA command support
Use BOT protocol or compatible bridge
TRIM batch failed
Timeout or bridge compatibility issue
Increase timeout value, decrease batch size
CRC mismatch in Real Test
Data area corrupted after TRIM
Possible bridge/SSD compatibility issue
Cannot stop during Verify Only
Reading a large file
Fixed in latest versions (cancel checked every 1MB)
12. License
The IODD TRIM Tool is Freeware.
Anyone can use it for free, and it may be freely copied and distributed.
This software is provided "AS IS".
Commercial sales are strictly prohibited.
The developer assumes no responsibility for any damages, including data loss, resulting from the use of this software.
Reverse engineering, decompiling, and source code extraction are prohibited.
Copyright (c) 2025-2026 IODD. All rights reserved.
This manual is based on IODD TRIM Tool v0.1.0-Beta.
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