While the NAND flash based solid state drive (SSD) has been widely adopted by both custom electronics and enterprise storages, the isolation of the file system and the information of the real status of the physical storage space will inevitably degrade the overall efficiency as well as the reliability of the storage and could become the bottleneck of the high-performance test systems. Open Channel Solid State Drive (OCSSD) has been proposed to resolve this dilemma by exposing details of the physical storage state to the host system. Base on the OCSSD architecture, this paper presents Strictly Sequential Writing (SSW), a highly efficient strictly sequential writing method to further reduce the garbage collection operations of SSD and ultimately prolong its lifetime and meanwhile improve the I/O performance of the storage system. The basic idea is to avoid any unwanted interruptions of random read/write operations for sequential write operations by exploiting the metadata of the file system. Thus, we can reduce the number of garbage collection operations a lot by properly allocating these unbroken sequential write operations. Then the reliability of the storage system will be greatly enhanced. We propose two strategies to optimize the identification and the reallocation of sequential write operations. The experimental results show that SSW can reduce the number of garbage collection operations on average 26.65% compared with the baseline scheme.