In this paper, we propose a novel file-sharing system called Local Cloud Storage (LCS), based on the leading-edge device called "wireless memory" such as Eye-Fi and Flash Air. Most interesting point is that wireless configuration of multiple devices is previously configured to communicate with each other. As a result, these devices are recognized as just a memory on operating systems. If a user adds a file into the mounted memory, the file is distributed to other memory via the pre-configured wireless connection unconsciously. In addition to the concept of LCS, we also propose a novel Cross-layer Simultaneous Data Transmission Mechanism (CSDTM) based on UDP broadcast in 802.11 for accelerating single-hop data simultaneous distribution between devices. Of course, a normal TCP can be adopted for data transmission in LCS. However, by adopting UDP broadcast, we can realize simultaneous data transmission to multiple receivers. Since UDP broadcast in wireless network is so unreliable, it hasn't been used for data transmission. However, by adding our designed application layer retransmission mechanism, CSDTM achieves 100% data transmission in our assumed environment. Through the performance evaluation of CSDTM, we show that it transmit data to four receivers within half the time a conventional method takes.